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1

Microstructural and magnetic response of austenitic stainless steels to plastic deformation

Slezák Martin, Palček Peter, Hrabovská Kamila, Životský Ondřej, Uhríčik Milan, Šnircová Melisa

System Safety : Human - Technical Facility - Environment

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2025

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Vol. 7, iss. 1

315--325

EN

The study investigates the influence of pressure-induced plastic deformation on the microstructural evolution, microhardness, and magnetic behavior of AISI 304 and AISI 316L austenitic stainless steels. Samples were subjected to different levels of compressive deformation and subsequently analyzed using optical microscopy, microhardness testing, and vibrating sample magnetometry (VSM). The microstructure after solution annealing consisted of polyhedral austenitic grains with numerous annealing twins, while after deformation, distinct signs of plastic strain were observed within individual grains. The microhardness measured perpendicular to the loading direction increased with the degree of deformation, reaching the highest values in the core of the samples, which confirms the non-uniform distribution of plastic deformation. Magnetic measurements revealed a noticeable increase in both saturation and remanent magnetization after plastic deformation, confirming the presence of deformation-induced α′-martensite. The coercive field decreased for AISI 304 but slightly increased for AISI 316L. The results demonstrate a clear correlation between mechanical strengthening and the magnetic response of austenitic steels subjected to plastic deformation.

2

Analysis of the microstructure and microhardness of the Stellite 1-WCL steel joint produced by the Direct Energy Deposition method

Małysza Marcin, Żuczek Robert, Wieliczko Piotr, Zięba Łukasz

Mechanik

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2025

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R. 98, nr 12

32--35

EN

The study presents the results of investigations on the microstructure, chemical composition, and microhardness of the cobalt alloy Stellite 1 joined to WCL tool steel, produced by the Direct Energy Deposition (DED) method. Analyses were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Based on EDS results from two layers, the nature of element diffusion was determined, and the joint zones were identified: the deposit, the transition zone, and the heat-affected zone (HAZ). A gradient distribution of elements was observed, indicating an extensive diffusion zone. Microhardness results confirmed the transition from the hard structure of the deposit to the softer substrate. It was found that the joint is characterized by structural continuity.

PL

W pracy przedstawiono wyniki badań mikrostruktury, składu chemicznego oraz mikrotwardości połączenia stopu kobaltu Stellite 1 ze stalą narzędziową WCL, wytworzonego metodą Direct Energy Deposition (DED). Analizy przeprowadzono z wykorzystaniem mikroskopii skaningowej (SEM) oraz mikroanalizy rentgenowskiej (EDS). Na podstawie wyników EDS z dwóch warstw określono charakter dyfuzji pierwiastków oraz zidentyfikowano strefy połączenia: napoinę, strefę przejściową i strefę wpływu ciepła (HAZ). Zarejestrowano gradientowy rozkład pierwiastków, wskazujący na rozległą strefę dyfuzyjną. Wyniki mikrotwardości potwierdziły przejście od twardej struktury napoiny do miększego podłoża. Stwierdzono, że połączenie charakteryzuje się ciągłością strukturalną.

3

Effect of major alloying elements Zn and Mg on microstructure and microhardness of AA7075 alloys and their composites

Mittal Prachi, Verma Ishu, Tomar Amit, Mahato Jayanta Kumar

Composites Theory and Practice

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2025

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R. 25, nr 2

90-101

EN

The present research work focuses on studying the effect of the major alloying elements on the microstructure and hardness of 7xxx series aluminium alloys and their composites. AA7075 aluminium alloy was used as the base material and different weight percentages of alloying elements zinc (Zn) and magnesium (Mg) were added at ratios 1:1, 2:1 and 3:1 to the base material. Afterwards, the modified aluminium alloys were used as matrix materials for the fabrication of aluminium alloy matrix composites (AAMCs) by adding different weight fractions of silicon carbide (SiC) as reinforcement material. Both the alloys and the AAMCs were fabricated by means of stir casting. XRD, SEM and EDX analysis of the modified aluminium alloys and their composites were carried out. Microstructures of the modified aluminium alloys and AAMCs were observed and the grain sizes were measured according to ASTM standards. Hardness tests of the fabricated specimens were carried out using Vickers microhardness testers and the hardness values were measured utilising the integrated software. It was observed that equiaxed grain structures were formed in both the modified Al alloys and their composites, indicating successful fabrication by means of the casting process; however, the average grain sizes of the fabricated specimens are dependent on the combination of wt% of reinforce ment and the composition of the Al alloys. Interestingly, a positive correlation with the weight percent ratio of Zn and Mg in the AA7075 was observed, indicating the potential for fine-tuning of the mechanical properties through proper selection of the alloying elements. It was also observed that the microhardness of the AAMCs fabricated with the mod ified Al alloys exhibits consistent improvement with an increasing weight fraction of SiC reinforcement, irrespective of the weight percentage ratio of the added Zn and Mg combination.

4

Acrylic resins for manufacturing dental prosthetic restorations – microstructural, micromechanical and tribological tests

Bojko Łukasz, Pałka Paweł, Ryniewicz Anna M., Ryniewicz Wojciech

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Vol. 73, nr 5

art. no. e154730

EN

When planning and manufacturing a removable dental prosthesis, efforts should be made to optimally distribute pressure without exceeding the threshold of the physiological capacity of tissues, especially since this type of restoration often causes prosthetic stomatopathies and atrophy of the bone substrate. The aim is to evaluate acrylic prosthetic structures in terms of microstructure, micromechanical parameters, resistance to movement in sliding friction, and wear resistance in the environment of physiological saline and artificial saliva. The research material includes removable prosthetic restorations made of acrylic resins manufactured in the Materials Science Laboratory at the Department of Dental Prosthetics of the Jagiellonian University Medical College. The clinical functionality of the restoration consists of adapting to individual biomechanical forces and creating the most favorable conditions for proper occlusion. Microstructure tests allowed the identification of the surface layer in wear defects and indicated the Vertex Rapid Simplified material as the least susceptible to internal defects and cracks, which may constitute potential places for the growth of fungi and bacteria. Micromechanical tests showed similar values of microhardness and longitudinal elastic moduli of the biomaterials tested. They may determine the strength and extent of the plate. Premacryl Plus had different and lower micromechanical parameters. Tribological tests facilitated a positive assessment of the effect of saliva on friction coefficients and forces. Reducing its value protects the tissues of the prosthetic base against the irritating effects of forces generated by the restoration under chewing and occlusion conditions.

5

Microstructural and Mechanical Characterization of Wire Arc Additive Manufactured Stainless Steel 316L

Kumar Jain Sudeep, Murtaza Qasim, Singh Pushpendra

Archives of Metallurgy and Materials

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2025

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Vol. 70, iss. 1

119--126

EN

Robotic arm technology coupled with Cold metal transfer (CMT) has revolutionized Wire arc additive manufacturing (WAAM), gaining widespread recognition in the aerospace, marine, and automotive sectors. In WAAM, managing residual stress poses challenges due to temperature gradients, phase transformations, and uneven cooling, leading to distortion and potential crack failures. This study is centered on the CMT-assisted fabrication of SS 316L WAAM utilizing a 1.2 mm diameter. It involves a comparative analysis of residual stress, microhardness, ultimate tensile strength, and percentage elongation between SS 316L WAAM, and the results were compared with those of wrought SS 316L. The WAAM sample quantified an average residual stress of 90.73 MPa (compressive), marking an 18% increase compared to the wrought stainless steel’s residual stress of 76.68 MPa (compressive). The microhardness profile of the WAAM sample revealed an average value of 269.51 HV0.5, signifying a substantial 4.48% increase over the wrought SS 316L microhardness of 257.94 HV0.5. The WAAM sample’s ultimate tensile strength was 577 MPa, 16.56% greater than the wrought SS 316L, having an ultimate tensile strength of 495 MPa, while their respective percentage elongation was 86% and 87%. WAAM demonstrated superior performance in terms of ultimate tensile strength, residual stress, and microhardness.

6

CMT Assisted Wire Arc Additive Manufacturing of SS 316L: Fabrication, Characterization, and Fractography

Kumar Jain Sudeep, Murtaza Qasim, Singh Pushpendra

Archives of Metallurgy and Materials

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2025

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Vol. 70, iss. 1

147--153

EN

CMT-WAAM, an advanced manufacturing technology, garners significant attention due to its ability to fabricate intricate components efficiently. In this investigation, a 40-layered structure was manufactured from SS 316L using the CMT-WAAM process, with the utilization of optimized process parameters. This research involved the analysis of microstructure and mechanical properties, including microhardness, tensile testing, and fractography, for both WAAM and wrought SS 316L. The UTS of WAAM reached 592.31 MPa and YS of 276.46 MPa, outperforming the UTS of wrought 316L, which was 557.62 MPa, and YS of 284.35 MPa. The PE of WAAM was 59.85%, while for wrought 316L, it was 53.20%, indicating that wrought 316L demonstrated a higher ductility than the WAAM part. The microhardness profile of WAAM showed an average value of 238.14 HV, indicating a 28% increase compared to the MH of wrought 316L, which was measured at 192.37 HV. The microstructure of CMT-WAAM displays δ-ferrite and γ-austenite, along with skeletal and lathy ferrites, similar in wrought 316L. The fractography analysis of tensile specimens exhibited numerous dimples, indicating favorable ductility in the fabricated structure. Therefore, the findings indicate that the CMT-WAAM process meets industrial requirements.

7

Microstructure and strengthening mechanism of a 316 stainless steel coating prepared by high-speed laser cladding on an aluminum alloy plate

Zhang Hengyuan, Cheng Wangjun, Yin Yuandong, Sun Yaoning, Li Xiao

Archives of Civil and Mechanical Engineering

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2025

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Vol. 25, no. 1

art. no. e15, 2025

EN

Aluminum alloy plates show great potential in energy storage and transportation applications. Nevertheless, the low surface strength of aluminum alloy plates negatively impacts their performance and safety. Aluminum alloys exhibit characteristics such as a low melting point, high reflectivity, and a rapid dilution rate, posing significant challenges for laser cladding coatings. This paper presented the surface modification mechanism of aluminum alloy plates. A stainless steel coating was successfully prepared on the surface of aluminum alloy substrates by using high-speed laser cladding technology. The microstructure, microscopic morphology, and microhardness of the coatings were conducted. The surface and sides of coatings were analyzed by XRD, SEM, EBSD, and microhardness testing, respectively. It is found that larger cellular crystals and carbides predominate at the junction of the substrate and the coating. The middle part of the 0.5-mm coating from the connection and the heat-affected zone are mainly dendritic crystals. The top of the 1-mm coating from the connection is mainly fine crystals. This means that local grain refinement occurs in the stainless steel coating via high-speed laser cladding. There is a transformation of FCC to BCC in the coating. Moreover, the cross-section of the coating exhibits a relatively high microhardness, ranging from 517 to 679 HV. The microhardness at the substrate is measured at 67 HV. The maximum microhardness of the coating is ten times that of the substrate. The bottom of the coating maintains a relatively high microhardness due to the presence of a large amount of carbides. The microhardness of the coating gradually increases from the middle to the surface of the coating. This is primarily attributed to solid solution strengthening and fine grain strengthening mechanisms. Columnar crystals at the metallurgical bond between the substrate and the coating transform into fine grains at the top, leading to a gradual refinement of the microstructure. High-speed laser cladding technology facilitates the enhancement of surface properties and the improvement of surface strength in traditional aluminum alloys.

8

Study of the effect of process factors on the wear rate and surface integrity in incremental point forming of AA6061 aluminum alloy

Mughir Walaa Amer, Jasim Hussein Hatem

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 3

84--95

EN

Incremental point forming is a contemporary method employed in sheet metal forming to achieve great flexibility in fabrication of intricate forms, eliminating the requirement for specific mold. According to its exceptional mechanical characteristics and low weight, this method is particularly employed in the production of aluminium alloys. The essential aim of this research is to examine the deformation mechanisms and discuss the mechanical properties of aluminium during the incremental forming process. The aim was to examine how various process parameters influence the surface properties, hardness, and wear resistance of the workpieces using aluminium alloy type AA6061. The parameters under investigation are increment step down size, feed rate, and spindle rotational speed. Furthermore, the impact of these factors on the forming process was investigated using several methodologies, including the Taguchi method for parameter optimization and surface analysis. The findings of this study demonstrate that spindle rotation speed exerted a substantial influence on both surface roughness and hardness, accounting for 63.41% for hardness and 52.19% for roughness. In terms of wear rate, the step size had the most significant impact, accounting for 48.53%.

9

Microplasma spraying of coatings from wire of heat-resistant nickel alloy Inconel 82 with laser melting

Korzhyk Volodymyr, Gao Shiyi, Khaskin Vladyslav, Bernatskyi Artemyi, Kislitsya Oleksandr, Voinarovych Sergii, Kuzmych-Yanchuk Yevhenii, Kaluzhnyi Sergyi, Hu Yanchao, Guirong Guirong

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 7

164--178

EN

The work is devoted to studying the technological capabilities of the processes of microplasma spraying of wires from heat-resistant nickel alloy Inconel 82 with further laser melting of the sprayed layers to produce narrow-path coatings during restoration of worn end faces of ribbed parts, used in nuclear engineering, aerospace and textile industry, etc. Numerical modeling by finite element method was applied to select the parameters of the modes of microplasma wire spraying and further laser melting of sprayed layers of Inconel 82 alloy. This made it possible to select the parameters of the modes with an accuracy of up to 20% (current 30-40 A at voltage 40 V, deposition speed 100 mm/min; radiation power 3.0 kW, defocusing spot 3 mm, remelting speed 750 mm/min). The value of the parameter of coating growth rate during microplasma spraying of Inconel 82 alloy wire was determined (it was equal to 1 mm of coating height / 1 cm of narrow path length / 1 min of spraying process duration). The work shows for the first time that the useful area of the microplasma spraying spot is close to the defocused laser radiation spot, ensuring unique possibilities for deposition of narrow paths and their laser remelting without hard phase burnout. This is experimentally confirmed by ~17% (290-350 HV) increase in the hardness of sprayed Inconel 82 layer (200-240 HV) during its remelting by radiation with power density of ~4.3·104 W/cm2. It was also determined that the features of structure formation during laser remelting of Inconel 82 alloy promote an enhancement of its corrosion resistance up to 1.5 times and increase in wear resistance by 20-40%, compared to sprayed coatings.

10

Influence of irradiation doses on the mechanical and tribological properties of polyetheretherketone exposed to electron beam treatment

Rakhadilov Bauyrzhan, Ormanbekov Kuanysh, Zhassulan Ainur, Andybayeva Gaukhar, Shynarbek Aibek, Mukhametov Yeldos

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 1

121--131

EN

This study investigates the effects of electron beam irradiation on the mechanical and tribological properties of polyetheretherketone (PEEK), with particular focus on modifications resulting from the application of Litol-24 lubricant. Samples of pre-treated PEEK were irradiated at doses of 100, 200, 400, and 600 kGy using the ILU-10 linear accelerator. Comprehensive analyses were conducted, including thermogravimetric analysis (TGA) to assess thermal stability, X-ray diffraction (XRD) to observe structural changes, and the impact of irradiation on microhardness. Tribological performance was evaluated using the ball-on-disc method. Results indicate that irradiation decreases microhardness by approximately 19% and modifies tribological behavior in a dose-dependent manner. TGA results showed subtle shifts in decomposition onset temperatures, with a reduction of about 10°C post-irradiation, while XRD revealed a 12% decrease in crystallinity, affecting mechanical properties. Further investigations demonstrated that lubrication, particularly under high-load conditions, could enhance PEEK’s operational characteristics post-irradiation. The study underscores the critical role of lubricants in improving the wear resistance and durability of PEEK, making it suitable for high-stress applications in mechanical engineering and manufacturing sectors. The analysis highlights the potential of integrating electron irradiation into existing material processing workflows to improve PEEK's properties, thereby extending its utility across various industrial applications. This approach offers a promising avenue for optimizing the performance and longevity of PEEK components, particularly in environments subject to extreme mechanical stresses.

11

Tribological Tests of Materials for Hip Joint Endoprosthesis Cups

Bojko Łukasz, Pałka Paweł, Osada Piotr, Makowska Elżbieta

Tribologia

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2024

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nr 4

7--22

EN

Hip joint alloplasty completely changes the cooperation conditions of the correct biological friction pair by introducing a cup and a head on a stem. When selecting an endoprosthesis, a choice should be made between a rigid tribological node and a flexible biobearing that absorbs locomotion loads, which better approximates the conditions in a normal joint. The aim of the study is to compare and evaluate the tribological and micromechanical parameters of selected biomaterials used for hip joint endoprosthesis cups. The conducted tests of wear resistance and determination of coefficients of friction, as well as microhardness and Young’s modulus tests, allowed us to determine which materials will be preferred for hip joint endoprosthesis cups. Based on the results of the tribological tests performed, the authors identify the most favorable tribological pair in the context of wear and coefficient of friction. Improving the tribological cooperation of the bearing pair used, reducing wear and generation of friction products in particular, may influence the articulation conditions of the endoprosthesis and the length of its survival in the body.

PL

Alloplastyka stawu biodrowego w sposób całkowity zmienia warunki współpracy prawidłowej biologicznej pary trącej poprzez wprowadzenie panewki oraz głowy na trzpieniu. Dobierając endoprotezę należy dokonać wyboru pomiędzy sztywnym węzłem tribologicznym a biołożyskiem podatnym, amortyzującym obciążenia lokomocyjne, które lepiej przybliża warunki panujące w prawidłowym stawie. Celem pracy jest porównanie i ocena parametrów tribologicznych i mikromechanicznych wybranych biomateriałów stosowanych na panewki endoprotez stawu biodrowego. Przeprowadzone badania odporności na zużycie oraz wyznaczenie współczynników tarcia, a także badania mikrotwardości i modułu Younga pozwoliły stwierdzić, które materiały będą najbardziej odpowiednie na panewki endoprotez stawu biodrowego. Badania tribologiczne pozwoliły na wyznaczenie najkorzystniejszej pary tribologicznej w kontekście zużycia i współczynnika tarcia. Poprawa tribologicznej współpracy zastosowanej pary łożyskowej, a szczególnie obniżenie zużycia i zmniejszenie generowania produktów tarcia może wpływać na warunki artykulacji endoprotezy i długość jej przeżycia w organizmie.

12

Analysis of the Microstructure And Mechanical Properties of Duplex Steel Joints

Witkowska Małgorzata, Kowalska Joanna, Chronowska-Przywara Kinga

Tribologia

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2024

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nr 1

147--158

EN

The article presents a study, the aim of which was to analyze the microstructure and mechanical properties of welded joints of austenitic-ferritic duplex steel X2CrMnNiN21-5-1. This steel is characterized by good resistance to various types of corrosion, good strength properties and good weldability. Due to all these advantages, it is used in many industry sectors, and the main joining techniques are welding technologies. In this study, two joining techniques were used, SMAW (Shielded Metal Arc Welding) and GTA (Gas Tungsten Arc). The obtained welded joints were subjected to: macroscopic and microscopic metallographic tests, mechanical tests (static bending test and microhardness measurements), diffraction tests, and wear resistance tests. The results showed that the microhardness of the welds is similar and does not depend on the welding method used. In the microstructure of the analyzed joints there are two phases: austenite (γ) and ferrite (δ), with different morphologies depending on the welding conditions, which affect the phase transformations. Material wear within the weld is greater than in the base material.

PL

Celem badań była analiza mikrostruktury i własności mechanicznych złączy spawanych stali austenityczno-ferrytycznej typu duplex X2CrMnNiN21-5-1. Stal ta charakteryzuje się dobrą odpornością na różnego rodzaju korozje, dobrymi własnościami wytrzymałościowymi i dobrą spawalnością. Dzięki tym wszystkim zaletom znajduje zastosowanie w wielu gałęziach przemysłu, a głównymi technikami jej łączenia są technologie spawalnicze. W pracy zastosowano dwie techniki łączenia metodą SMAW (Shielded Metal Arc Welding) i GTA (Gas Tungsten Arc). Uzyskane złącza spawane poddano: badaniom metalograficznym makro- i mikroskopowym, badaniom mechanicznym (statyczna próba zginania i pomiary mikrotwardości), badaniom dyfrakcyjnym oraz badaniom odporności na zużycie. Wyniki badań pokazały, że mikrotwardości spoin są zbliżone i nie zależą od zastosowanej metody spawania. W mikrostrukturze analizowanych złącz występują dwie fazy austenit (γ) i ferryt (δ) o zróżnicowanej morfologii zależnej od warunków spawania, które wpływają na przemiany fazowe. Zużycie materiału w obrębie spoiny jest większe aniżeli w materiale rodzimym.

13

Właściwości warstwy wierzchniej wybranych stopów metali po cięciu laserem

Skoczylas Agnieszka

Stal, Metale & Nowe Technologie

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2024

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nr 3-4

31--40

EN

The article analyses the properties of the surface layer of the C45, X5CrNi18-10, 1.7218, 700MC steel elements after laser cutting, focusing on the stereometric and physical properties of the surface layer. The parameters of 2D and 3D surface roughness and microhardness of the surface layer on diagonal sections are analysed and imperfections are determined. Due to the occurrence of zones of different surface roughness on the surface of the cut elements, the roughness parameters Ra, Rpk and Rvk were measured in the “entrance zone” and “exit zone” of the laser beam. In the case of the C45 and X5CrNi18-10 steel samples, a large difference in the surface quality between the zones was found. For the elements made of the C45, 700 MC and 1.7218 steel, imperfections are located at the lower edge. In the case of all the engineering materials, an increase in microhardness was obtained, ranging from 11% to 137%, and the thickness of the heat affected zone ranged from 10 μm to 250 μm.

14

Evaluation of microstructural and mechanical qualities in optimised TIG-welded SDSS 2507 joints

Kumar Sujeet, Srinivas Madugula Naveen, Kumar Naveen, Giri Jayant, Fatehmulla Amanullah

Materials Science Poland

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2024

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Vol. 42, No. 4

163--179

EN

Super duplex stainless steel (SDSS) is gaining attraction owing to its excellent mechanical strength and superior corrosion resistance. In this study, tungsten inert gas (TIG) was implemented for welding the SDSS thin sheet. The Taguchi method and analysis of variance (ANOVA) were carried out by selecting L25 orthogonal arrays. The optimum TIG parameters were a welding current of 75 A, an arc potential of 15 V, a welding rate of 120 mm/min, and an argon gas consumption rate of 12 L/min. An ANOVA study found that welding current (46.95%) was the largest contributor in producing the excellent welded joint. The microstructural research indicated increased grain size in the heat-affected zone (HAZ) and fusion zone (FZ), represented by distinct grain boundary layers, intragranulars, and Widmanstätten austenite. This was due to heat input and rapid cooling inclusion as well as re-crystallisation of the ferrite matrix. The elemental mapping analysis showed that chromium must be present to generate a shielding oxide layer, which decreased from 25.50% in the parent material to 23.40% in the TIG welded joint. The tensile test found that TIG welds had an ultimate tensile strength (UTS) of 789 MPa. This value was equivalent to the base metal UTS value of 800 MPa. The micro-hardness test of the TIG welded joint confirmed that the HAZ (350 HV) and FZ (325 HV) were higher than that of the base metal (305 HV). The hardness value near the FZ boundary experienced a significant increase due to the development of hard microscopic components and element migration during the TIG process.

15

Microstructural study of the composite nickel based, containing different Al amounts, sintered by an unconventional technique and forged

Bendriss Houceme, Boudebane Said, Lemboub Samia, Benselhoub Aissa

Inżynieria Materiałowa

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2024

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Vol. 45, nr 3

8--17

EN

The aluminum-enriched composite with the composition of Udimet 720 alloy was developed using an unconventional two-step sintering process. The first occurred at 1380°C for 0.5 h and the second at 1180°C for 3 h. The sintered material was then forged at 1200°C under a load of 50 kG and with a fall height of 220 mm, in order to achieve the clusters fragmentation of hard components, followed by the homogenization annealing at 800°C for 1.5 h. The consolidation technique included solution treatment at 1080°C and aging at 800°C with various holding times. The investigation techniques by X-ray diffraction analysis (XRD) and observations under a scanning electron microscope (SEM) with semi-quantitative analyses (EDS) have offered the possibility to reveal the aluminum addition’s impact and the holding time aging on the material’s microstructural evolution. The sintered alloy with a high Al content (5.25 %) exhibits a complex structure composed of metallic matrix γ, the chromium carbide Cr23 C6 , and a large variety of binary intermetallics. Despite this, the solution treatment caused an almost complete dissolution of these compounds, and consequently, a saturation of the nickel cubic lattice. An increase in precipitation phenomenon was, due to the formation of the intermetallic γ’ (Ni, Co)3 (Al, Ti), and then, the alloyed chromium carbide (Cr, Co, Ni, Mo, Ti)23 C6 , led to a noticeable hardening of the metal matrix, reaching a microhardness of 700 HV0.1.

PL

Opracowano kompozyt wzbogacony aluminium o składzie stopu Udimet 720 w niekonwencjonalnym dwuetapowym procesie spiekania. Kompozyt spiekano w temp. 1380°C przez 0,5 h, a następnie w temp. 1180°C przez 3 h. Spiekany materiał poddano kuciu w temp. 1200°C pod obciążeniem 50 kG i wysokości opadania 220 mm, w celu uzyskania fragmentacji skupień twardych składników, a następnie wyżarzaniu homogenizującym w temp. 800°C przez 1,5 h. Technika konsolidacji obejmowała obróbkę przesycającą w temp. 1080°C i starzenie w temp. 800°C z różnymi czasami przetrzymywania. Techniki badawcze polegające na analizie dyfrakcji promieni rentgenowskich (XRD) i obserwacje pod skaningowym mikroskopem elektronowym (SEM) wraz z analizami półilościowymi (EDS) umożliwiły ujawnienie wpływu dodatku aluminium i czasu utrzymywania starzenia na ewolucję mikrostruktury materiału. Spiekany stop o wysokiej zawartości Al (5,25%) wykazywał złożoną strukturę, na którą składały się: metaliczna osnowa γ, węglik chromu Cr23 C6 i duża różnorodność binarnych związków międzymetalicznych. Mimo to obróbka roztworowa spowodowała niemal całkowite rozpuszczenie tych związków, a w konsekwencji nasycenie sześciennej sieci niklu. Nasilenie zjawiska strącania osadów spowodowane utworzeniem się międzymetalicznego γ' (Ni, Co)3 (Al, Ti), a następnie stopowego węglika chromu (Cr, Co, Ni, Mo, Ti)23 C6 , doprowadziło do zauważalnego utwardzenia osnowy metalicznej, osiągającego mikrotwardość 700 HV0,1.

16

Effect of graphite nanoparticles on mechanical properties of FSPed aluminum surface composite

Kumar Dinesh, Singh Satnam

Composites Theory and Practice

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2024

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R. 24, nr 1

33--38

EN

Friction stir processing (FSP) is a manufacturing technique that can be employed to produce aluminum 6082 surface composites (ASCs). These ASCs display considerable increases in hardness and tensile strength, which makes them ideal for a wide variety of automotive applications. One example is piston skirts that are used in the cylinder chamber. The primary emphasis of this research is to investigate the accumulative impact that several passes have on Al 6082 surface composites that were filled with graphite nanopowder. The mechanical properties and microstructure of the fabricated composites were studied in order to accomplish this goal. The microstructural investigation showed that the graphite nanopowder particles were evenly distributed throughout the Al-6082 alloy. In addition, better dispersion of the graphite nanopowder was seen throughout the matrix material as the number of passes made during friction stir processing was increased. This may be explained by the reduction in grain size that occurs inside the aluminum metal matrix composites (AMMCs) that are produced as a consequence. According to the results of the research, the microhardness of the material grew to 105.3 HV after the third pass of the tool, and its maximum tensile strength rose to 215±3 MPa. In the ASCs that fabricated after three passes of friction stir processing, the smallest grain size that was measured was 24 micrometers.

17

Microhardness and Elastic Properties Evaluation of WC-TiC Coatings Obtained by Arc Spraying Process

Haraga Radu, Chicet Daniela, Toma Stefan, Carlescu Vlad, Bejinariu Costica

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 2

795--801

EN

Fulfilling the basic role of hard thermal sprayied coatings is closely related to the value of its microhardness. The quality of such a layer depends on several variables, the main categories being: spray method (flame spray, electric arc, plasma spray, cold spray, etc.), spray parameters (spray distance, voltage and intensity, working atmosphere, direction of the spray jet, etc.) and the materials used (chemical composition of the coating materials, quality and texture of the substrate). In this study, the microhardness, elastic properties and cohesion of a coating made of hard cored wire (Praxair - Tafa) by electric arc spraying process on a low alloy steel substrate, were analyzed. The cored wire has as main hard elements WC (about 26%) and TiC (about 6%), the rest of the chemical elements present being: Cr (14%), Ni (4.5%), B (1.87%), Si (1.25%) and the Fe balance. The micro-hardness was evaluated onto the surface of the coating, previously prepared by grinding to reduce the as-coated roughness. The method based on recording the forcess generated during the indentation with simultaneous measurement of the load - depth curve (with UMT 2M-CETR microtribometer) were used for the microhardness evaluation. In order to analyse the cohesion of the coated layer, scratch tests with progressive loading (10N, 15N and 20N) were performed on the same microtribometer. Tests have shown that the metal matrix uniformly includes the hard particles arised from the core of the wire, and at the microstructural level, the microhardness varies significantly, depending on the hardness of the particles on which the indentor tip applies the loading forces. However, the overall behavior of the coatings thus realized is a satisfactory one, being, as a general behavior, in the average required by the applications of such a layer.

18

Investigation on the Microstructure, Microhardness and Tensile Strength of Stir-Casted A713-TiB2 Composites

Rangrej Shyam, Pandya Shailesh, Menghani Jyoti

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 3

1251--1260

EN

A parametric experimental investigation has been conducted to investigate effects of stir casting process parameters on recently developed A713-TiB2 composites. The manufacturing process involved varying the stirring time (5, 10, and 15 minutes) and speed of stirring (500, 600 & 700 rpm). The microstructure and mechanical properties of the manufactured composites were evaluated by analyzing the effects of the varying stirring speeds and times. The analysis techniques used include optical microscopy (OM), scanning electron microscopy (SEM), micro-hardness and tensile testing. Grain size analysis of the as-cast MMCs revealed that coarser grain structure was observed at lower stirring time and lower speed. Finer grain structure was achieved by increasing stirring time and speed. Microhardness and tensile strength was observed to be affected by both stirring speed and stirring time, as demonstrated by the test results. The uniform dispersion was attained when stirring was done at 600 rpm for 10 minutes. Further increase in stirring speed and stirring time leads to the reduction in microhardness and tensile strength. In the present study, the relationship between the microstructure and mechanical properties of the A713-TiB2 composite and the processing parameters such as stirring speed and stirring time have been investigated.

19

Tribological performance of gas tungsten arc welded dissimilar joint of sDSS 2507/IN‑625 for marine application

Maurya Anup Kumar, Khan Waris Nawaz, Patnaik Amar, Adin Mehmet Şükrü, Chhibber Rahul, Pandey Chandan

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 1

art. no. e23, 2024

EN

The present study utilizes a slurry-pot wear tester to investigate the relationship between slurry concentration and slurry-erosion performance of sDSS 2507/IN625 dissimilar weld joint (DWJ). Varying slurry concentrations (10 and 30 wt.% silica sand) were utilized to investigate erosion, weight loss, and wear mechanisms in severe environments. The study aimed to provide an in-depth knowledge of erosion behaviors by analyzing surface characteristics, microstructure characteristics, and material removal mechanisms. The electron probe micro-analyzer studied weld zone element segregation and scanning electron microscopy (SEM) examined microstructure and erosion mechanism. ER2594 filler weld shows higher microhardness as compared to weld fabricated using ERNiCrMo-3 filler metal. Sand particle density, particle-to-surface contact, particle interactions, and fluid impacts increase cumulative weight loss and decrease erosion rate per unit solids weight. Slurry concentration increased weight loss by 23% for sDSS 2507 BM and 33% for IN-625 BM. ER2594-LHI lost 72% and ERNiCrMo-3-LHI 77% more weight with increasing slurry concentration. Filler ERNiCrMo-3 has less erosion wear than filler ER2594 as the concentration of slurry increases. SDSS 2507 BM and IN-625 BM erode 1.45 and 1.8 times faster with increasing slurry concentration, respectively. The erosion rate of ER2594-LHI and ERNiCrMo-3-LHI increases 0.85 and 1.2 times with slurry concentration. SEM analysis of the worn surface exhibits mixed cutting–ploughing modes coexisting with the formation of craters. The material removal has predominantly occurred from the cutting and ploughing mechanism, whereas the characteristic presence of craters and frontal and lateral lips is also found across the entire surface. The results from this study suggest the optimum heat input to be maintained during weld fabrication of sDSS 2507/IN-625 using ER 2594 and ERNiCrMo-3 filler metals for enhanced resistance against slurry erosion wear. Also, an insight into the wear mechanism helps in understanding the effect of microstructural features on the wear performance of welds in operational conditions.

20

Influence of Different Polishing Methods on Surface Roughness and Microhardness of Dental Composites

Mierzejewska Żaneta A., Łukaszuk Kamila, Choromańska Magdalena, Zalewska Anna, Borys Jan, Antonowicz Bożena, Kulesza Ewa

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 1

268--279

EN

The surface roughness and microhardness of dental composites greatly affects the durability of restorations. To evaluate the effect of three different polishing systems (Sof-Lex, Enhance+PoGo, Kenda) on the surface roughness and microhardness of microhybrid (Herculite XRV, Filtek Z250 and Charisma Flow) and nanohybrid (Herculite XRV Ultra, Filtek Z550 and Charisma Bulk Flow) composites resin used for dental fillings. Six different composites were used in the study. From each material, 40 cylinder-shaped samples were made. All samples were polymerized and polished using three different methods. To evaluate surface roughness a confocal laser microscope was used, and microhardness was determined using a universal Vickers hardness tester.The data were analysed using the one-way ANOVA test at a significance level of 0.05 for both tests. The smoothest surfaces in all groups of composites were obtained for control samples. Also in all groups of composite samples no statistically significant differences were found between the Sof-Lex and Enhance+PoGo. The measurement of surface roughness obtained for the Kenda system showed significantly lower values than for the other two methods. The surfaces of the control samples showed statistically significantly lower microhardness values compared to all polishing systems for all six tested resin composites, additionally no statistically significant differences were found between all finishing and polishing methods. Regardless of the finishing and polishing method used, the lowest microhardness values among microhybrid materials were found for Charisma Flow, while among nanohybrid materials the lowest values were obtained for Herculite HRV Ultra. Finishing and polishing increases the microhardness of microhybrid and nanohybrid composite resin. The use of Kenda three step polishing system resulted in smoother surface for all tested composite materials compared to the Sof-Lex and Enhance+PoGo systems, while the finishing and polishing method had little effect on the microhardness of the surface.