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1

Influence of Thin Coatings Formed by ALD Techniques on the Properties of Ti13Nb13Zr Titanium Alloy

Piotrowska Katarzyna, Madej Monika

Tribologia

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2022

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nr 1

65--73

EN

The article evaluates the properties of oxide films: Al2O3 and TiO2, deposited using the ALD method on the Ti13Nb13Zr alloy. It presents the results of examining the geometrical structure of the surface, nanohardness and tribological tests. The surface’s geometrical structure was tested through optical microscopy, and nanohardness was determined using the instrumental indentation method with a Berkovich indenter. The modelling tribological tests were performed in a reciprocating motion under the conditions of technically dry friction and with lubrication using Ringer's solution. An analysis of the results of tribological tests indicates that the films were characterised by lower motion resistances and wear with respect to the Ti13Nb13Zr alloy. Hardness measurements indicate that, as a result of deposition of the films, the hardness increased by approximately 51% in the case of the Al2O3 film and by approximately 44% in the case of the TiO2 coating. The produced test results constitute a source of knowledge about the Ti13Nb13Zr alloy, oxide films and the possibilities of their potential application to low-load biotribological systems.

PL

W artykule dokonano oceny właściwości warstw tlenkowych: Al2O3 i TiO2 osadzonych metodą ALD na stopie Ti13Nb13Zr. Przedstawiono wyniki badań struktury geometrycznej powierzchni, nanotwardości oraz testów tribologicznych. Strukturę geometryczną powierzchni zbadano przy użyciu mikroskopii optycznej, a nanotwardość określono metodą instrumentalnej indentacji przy użyciu wgłębnika Berkovich’a. Modelowe badania tribologiczne przeprowadzono w ruchu posuwisto-zwrotnym w warunkach tarcia technicznie suchego oraz ze smarowaniem płynem Ringera. Analiza wyników badań tribologicznych wskazała, że powłoki charakteryzowały się mniejszymi oporami ruchu oraz zużyciem w odniesieniu do stopu Ti13Nb13Zr. Pomiary twardości wskazują, że w wyniku osadzenia powłok twardość wzrosła o około 51% w przypadku powłoki Al2O3 oraz o około 44% w przypadku powłoki TiO2. Uzyskane wyniki badań stanowią źródło wiedzy na temat stopu Ti13Nb13Zr, powłok tlenkowych oraz możliwości ich potencjalnego zastosowania w niskoobciążonych systemach biotribologicznych.

2

Influence of Pre-Hardened Gx120mn13 Cast Steel on the Tribological Properties under Technically Dry Friction

Kalandyk Barbara, Zapała Renata, Madej Monika, Kasińska Justyna, Piotrowska Katarzyna

Tribologia

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2022

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nr 3

17--24

EN

This paper presents the results of tribological tests on high manganese GX120Mn13 cast steel under technically dry friction conditions. The tests were carried out using a TRB3 ball-on-disc tribometer using a 6mm-diameter SiC ball as a counter-sample for a specimen made of GX120Mn13 cast steel containing a localised prehardening area on the test surface with a hardness of approximately 597 HV10 (the non-hardened area had a hardness of approximately 325–364 HV10). During the test, the ball travelled in a 16.68 mm diameter circle and passed through both hardening and non-hardened areas. The resulting erosion marks were assessed using an optical profilometer and scanning microscope tests, which showed that the maximum depth of erosion in the previously hardening area was 0.77 µm and was more than twice as deep as in the non-hardened areas surveyed. In contrast, the area of attrition was twice as small as in the non-hardened area located in the axis of the previously applied load and more than three times smaller, but in the area located on the side of the axis and 8.34 mm away from it. Thus, from the point of view of the abrasion resistance of GX120Mn13 cast steel, the validity of its prior hardening before the operation was confirmed.

PL

W artykule przedstawiono wyniki badań tribologicznych wysokomanganowego staliwa GX120Mn13 w warunkach tarcia technicznie suchego. Badania przeprowadzono przy użyciu tribometru TRB3 typu ball–on– disc stosując jako przeciwpróbkę kulkę z SiC o średnicy 6mm dla próbki wykonanej ze staliwa GX120Mn13 zawierającej na powierzchni badanej lokalny obszar wcześniej umocniony o twardości ok. 597 HV10 (obszar nieumocniony posiadał twardość ok 325–364 HV10). Kulka w czasie testu poruszała się po okręgu o średnicy 16.68 mm i przechodziła zarówno przez obszar umocniony, jak i nieumocniony. Otrzymane ślady wytarcia oceniano za pomocą badań wykonanych na profilometrze optycznym i mikroskopie skaningowym. Na podstawie przeprowadzonych badań wykazano, że w obszarze wcześniej umocnionym maksymalna głębokość wytarcia wynosiła 0.77 µm i była ponad dwukrotnie mniejsza niż w badanych obszarach nieumocnionych. Z kolei pole wytarcia było dwukrotnie mniejsze niż w obszarze nieumocnionym, znajdującym się w osi przyłożonego wcześniej obciążenia i ponad trzykrotnie mniejsze w porównaniu z obszarem znajdującym się z boku osi i oddalonym od niej o 8.34 mm. Tym samym, z punktu widzenia odporności na zużycie ścierne staliwa GX120Mn13, potwierdzono słuszność jego wcześniejszego umocnienia przed eksploatacją.

3

Cavitation Erosion Resistance of High-Alloyed Fe-Based Weld Hardfacings Deposited Via SMAW method

Szala Mirosław, Hejwowski Tadeusz

Tribologia

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2022

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nr 4

85--94

EN

In order to investigate the cavitation erosion (CE) resistance of high-alloyed ferrous hardfacings, the three different deposits were pad welded by the shielded metal arc welding (SMAW) method. Consumable electrodes differed in the content of carbide-forming elements, and pad welds were deposited onto the S235JR structural. The CE tests, conducted according to ASTM G32 standard, indicated that hardfacings reveal lower mass loss than the reference stainless steel AISI 304 (X5CrNi18-10). The hardfacings show increasing resistance to CE in the following order: Cr-C < Cr-C-Mo < Cr-C-Mo-V-W. The reference steel revealed more than twenty times higher material loss in the CE test than Cr-C-Mo-V-W hardfacing, which had outstanding hardness (825HV0.3). The profilometric measurements and scanning electron microscopy investigations showed large changes in valley and peak sizes of the roughness profiles for materials which displayed high erosion rates. The erosion mechanism of the coatings can be classified as brittle-ductile and relies on cracking, chunk removal of material, pits and craters formation, and deformation of fractured material tips and edges. Hardfacing materials failed primarily due to brittle fractures with different severities. Specimen surface degradation follows the changes in Ra, Rz, Rv, and Rp roughness parameters and well-corresponds to the proposed roughness rate (RR) parameter.

PL

W celu zbadania odporności na erozję kawitacyjną (EK) wysokostopowych napoin na osnowie żelaza napawano trzema materiałami metodą SMAW. Elektrody otulone różniły się zawartością pierwiastków węglikotwórczych. Napoiny wykonano na stali konstrukcyjnej S235JR. Testy EK, przeprowadzone zgodnie z normą ASTM G32, wykazały niższy ubytek masy napoin w porównaniu do referencyjnej stali odpornej na korozję AISI 304 (X5CrNi18-10). Napoiny wykazują rosnącą odporność na EK w następującej kolejności: Cr-C < Cr-C-Mo < Cr-C-Mo-V-W. Referencyjna próbka stalowa wykazała w teście EK ponad dwudziestokrotnie większy ubytek materiału niż napoina Cr-C-Mo-V-W, która miała wyjątkowo wysoką twardość (825HV0.3). Pomiary profilometryczne i badania przeprowadzone przy użyciu skaningowego mikroskopu elektronowego wykazały duże zmiany wielkości dolin i szczytów profilu chropowatości dla materiałów wykazujących wysoką szybkość erozji. Mechanizm EK powłok można sklasyfikować jako krucho-plastyczny i opiera się na pękaniu, usuwaniu kawałków materiału, tworzeniu wgłębień i kraterów oraz deformacji pękniętych fragmentów kraterów oraz deformacji wyodrębnionych szczytów i krawędzi materiału. Napawany materiał podlega niszczeniu przez jego pękanie w różnym nasileniu. Degradacja powierzchni próbek pogłębia się wraz ze zmianą parametrów chropowatości Ra, Rz, Rv i Rp i dobrze koresponduje z proponowanym parametrem RR (zmiana chropowatości pow. degradowanej).

4

Badania konstrukcyjnych elementów drewnianych z wykorzystaniem urządzenia Woodtester®

Jaskowska-Lemańska Justyna

Materiały Budowlane

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2022

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nr 11

141--144

PL

W artykule przedstawiono zależności korelacyjne pomiędzy cechami mechanicznymi a wynikami badań sklerometrycznych krajowego drewna sosnowego. Siła uzyskanych korelacji była zróżnicowana. Najsilniejszą korelację do wyników badań sklerometrycznych uzyskano w przypadku gęstości drewna, a w dalszej kolejności do wytrzymałości na zginanie i ściskanie. Dodatkowo zaprezentowano funkcje korelacyjne sprowadzone do wartości kwantylowej, mogące stanowić podstawę do oceny cech fizykomechanicznych drewna w istniejących konstrukcjach, przede wszystkim zabytkowych.

EN

The paper presents correlations between mechanical properties for domestic pine wood and the results of sclerometric tests. The correlation power varied, the strongest correlation to the results of sclerometric tests was obtained for wood density, followed by flexural and compressive strength. In addition, the paper presents correlation functions reduced to a quantile value, which can provide a basis for evaluating the physical and mechanical properties of timber in existing structures, in particular historic ones.

5

Effect of novel grain refiner and Ni alloying additions on microstructure and mechanical properties of Al-Si9.8-Cu3.4 HPDC castings – optimization using Multi Criteria Decision making approach

Apparao K. Ch., Bannaravuri Praveen Kumar, Pulisheru Kumar Swamy, Francis E. D., Sunny Kalakanda Alfred, Babu Rao Gadudasu, Daniel P. Freedon, Kumar Birru Anil

Materials Science Poland

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2022

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Vol. 40, No. 1

9--24

EN

Studies dealing with process improvement of aluminum alloys and their grain structure refinement are the current area of interest in casting companies and foundries, the aim being to enhance the properties of the base metal. In this study, the microstructural and mechanical properties of commercial Al-Si9.8-Cu3.4 alloy die castings influenced by different additions of Al-3.5FeNb-1.5C master alloy (viz. 0 wt.%, 0.1 wt.%, and 1.0 wt.%) as a new grain refiner and Al-6Ni master alloy (viz. 0 wt.%, 0.5 wt.%, and 5.0 wt.%) as an alloying element have been investigated. A multi-criteria decision-making approach for the improvement of the die casting process was performed using grey relational analysis (GRA) and TOPSIS analytical techniques. It was observed that the primary aluminum α-grains were significantly refined, particularly at the lower addition level 0.1 wt.% of Al-3.5FeNb-1.5C, and conversely, poor grain refining efficiency was observed at a higher addition level 1.0 wt.% of Al-3.5FeNb-1.5C. Due to the refinement by Al-3.5FeNb-1.5C grain refiner and the effect of Ni alloying element additions, the ultimate tensile strength (UTS) and hardness (Brinell and micro) of the Al-Si9.8-Cu3.4alloy are improved, particularly at 0.1 wt.% of Al-3.5FeNb-1.5C and 0.5 wt.% of Al-6Ni master alloys. Quantitatively, UTS, Brinell hardness, and microhardness values have been increased by 12.3%, 7.0%, and 20%, respectively.

6

Deformation behaviour of high-manganese steel with addition of niobium under quasi-static tensile loading

Jabłońska Magdalena Barbara, Jasiak Katarzyna, Kowalczyk Karolina, Bednarczyk Iwona, Skwarski Mateusz, Tkocz Marek, Gronostajski Zbigniew

Materials Science Poland

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2022

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Vol. 40, No. 3

1--11

EN

In this paper, the heat generated during deformation under the static testing of high-manganese TWIP steel with addition of niobium was determined. The research combined the interaction of heat generated during deformation, mechanical properties, hardness and microstructure. Temperature and strain were measured simultaneously using infrared (IR) thermography and digital image correlation (DIC) method. The average temperature measured at the necked region equals 42°C at the strain rate of 0.001 s−1 and exceeds 100°C at 0.5 s−1. Therefore at large strains, a reduction in stress was observed. The course of the hardness change coincides very well with the strain changes, however, at the strain rate of 0.5 s−1 near to the necking area the hardness equals to 360 HV2, whereas at the lower strain rates it equals to 370 HV2. These changes are connected mainly with increase in temperature to >100°C

7

Pelletizing of Various Municipal Solid Waste: Effect of Hardness and Density into Caloric Value

Suryawan I. Wayan Koko, Fauziah Eva Nur, Septiariva Iva Yenis, Ramadan Bimastyaji Surya, Sari Mega Mutiara, Ummatin Kuntum Khoiro, Lim Jun-Wei

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 2

122--128

EN

Density and hardness are physical parameters in the manufacturing of refuse derived fuel (RDF) pellets. In making pellets, a high heating value for the combustion system is desired. This research aimed to analyze the mixture of municipal solid waste to its density and hardness and study its correlation to heating value. The variable used in this research is a mixture of paper waste and garden waste and food scraps and garden waste. The density and hardness for the mix of paper waste and garden waste were 1970.6 to 2474.8 kg/m3 and 37.8–42.8 HA, respectively. The mixture of food waste and garden waste has density and hardness of 1822 to 2276.7 kg/m3 and 17.4–37.8 HA. The correlation between density and hardness on heating values did not reach a significance of 0.05, so there was no strong relationship between density and hardness on heating values.

8

Properties and characteristics of alkali treated Calotropis gigantea fiber-reinforced particle-filled epoxy composites

Jeyapragash R., Sathiyamurthy S., Srinivasan V., Prithivirajan R., Swaminathan G.

Composites Theory and Practice

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2022

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R. 22, nr 2

99--105

EN

The presence of particles and fibers as reinforcement in a polymer matrix greatly enhances the mechanical properties. Agricultural residues and natural fibers are commonly used nowadays due to the fact that they easily decompose even after a longer period and they are eco-friendly in nature. f Fiber that was extracted from stem of Calotropis gigantea was selected as reinforcement in the present investigation. Initially the fiber was treated with a sodium hydroxide solution and CG fiber-epoxy composites were prepared. The properties of alkaline treated CG fiber-reinforced epoxy composites were further improved by the addition of particles such as chitosan, red mud and rice husk. Properties such as the tensile strength, flexural strength, impact toughness, hardness, water absorption, thickness swelling behaviour, specific wear rate and coefficient of friction were evaluated and compared. The XRD pattern of the chemically treated CG fiber-reinforced parrticle-filled epoxy composites was presented in the present study.

9

Aluminium oxide (Al2O3)-few layer graphene (FLG) reinforced aluminium hybrid composites

Kaykılarlı Cantekin, Altınışık Zehra, Kılıç E. Can, Uzunsoy Deniz, Yeprem H. Aygül

Composites Theory and Practice

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2022

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R. 22, nr 2

72--78

EN

The present study investigates the microstructural and mechanical properties of few layer graphene (FLG, 0.1 to 5 wt.%) and aluminium oxide (Al2O3, 4 to 20 wt.%) reinforced Al6061 matrix composites prepared via mechanical alloying (MA), uniaxial pressing and pressureless sintering. The effects of the amounts of Al2O3 and FLG were studied. MA was carried out at 300 rpm for 3 h in a planetary ball mill in argon atmosphere. The mechanically alloyed (MAed) powders were compacted via uniaxial pressing (400 MPa) and sintering (620°C, 2 h). The microstructural and mechanical properties of the Al-xAl2O3-yFLG powders and bulk samples were investigated via X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), the Archimedes’ method and a hardness test. In the XRD analysis, the aluminium carbide (Al4C3) phase was not detected. The SEM, LM micrographs and EDS results show that the produced composites have a homogeneous structure. Based on the Archimedes’ method, the densification rates of the reinforced samples were higher than the unreinforced sample. The Al-20Al2O3-3FLG sample exhibited the highest relative density, 99.25%. According to the hardness measurements, the highest hardness value was 87.28 HV for the Al-20Al2O3-1FLG composite and increased twofold compared to Al6061.

10

The Effect of 0.2% Addition of Mg, Co and Ce on Microstructure and Mechanical Properties of 1xxx Series Aluminium Alloy Castings Designed for Overhead Transmission Lines

Koprowski Paweł, Lech-Grega M., Wodzinski Łukasz, Augustyn Bogusław, Boczkal Sonia, Uliasz Piotr, Ożóg Mirosław

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

303--309

EN

The effect of 0.2% addition of Mg, Co and Ce to 99.9% cast aluminium was studied by evaluation of changes in microstructure and mechanical properties. The microstructure was analyzed by scanning electron microscopy and transmission electron microscopy. The Al99.9 alloy contained only Al-Fe-Si phase particles. Similar Al-Fe-Si particles were observed in alloy with 0.2% Mg addition, because this amount of magnesium was fully dissolved in the solid solution. The addition of cobalt resulted in the formation of Al9.02Co1.51Fe0.47 phase particles assuming the shape of eutectic plates. The electron backscattered diffraction map made for the alloy with 0.2% Co addition showed numerous twin boundaries with distances between them in the range from 10 to 100 µm. The addition of cerium was located in the grain boundary area. Cerium also gave rise to the formation of two types of particles, i.e. Al4Ce and Al-Ce-Fe-Si. The Al-Ce-Fe-Si phase is a nucleation site for the Al4Ce phase, which forms eutectic plates. The results showed that the introduction of additives increases the mechanical properties of the cast materials. The 99.9% cast aluminium has a hardness of 16.9 HB. The addition of 0.2% by weight of Mg, Co, Ce increases this hardness to 21.8 HB, 22.6 HB and 19.1 HB, respectively.

11

Synthesis and Characterization of Bioceramics Reinforced Aluminium Matrix Composites

Bhuvaneswari V., Rajeshkumar L., Saravanakumar R., Balaji D.

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1217--1226

EN

Current work attempts to fabricate aluminium alloy AA2219 metal matrix composite (AMC) reinforced with natural bio-based sea shell powder (SSP) which is a ceramic material, in view of improving the mechanical and tribological properties. SSP was characterized by X-Ray Diffraction (XRD) to assess its chemical constituents and particle size. Stir casting route was adopted for fabricating AMCs reinforced with 1, 2 and 3 wt.% of SSP. Energy Dispersive X-ray Spectroscopy (EDS) was used to analyse the formation of secondary elements during casting and scanning electron microscopy (SEM) was used analyze the surface morphology of the composite specimen before and after tribological tests. Hardness, Compressive strength and tribological properties were evaluated using appropriate tests and corresponding ASTM standards. Characterization methods revealed that the formation of secondary elements was very low at 3 wt.% of SSP when compared with other compositions. Hardness and compressive strength was found to be maximum for 3 wt.% of SSP while the specific wear rate and coefficient of friction values were found to be lesser for the same composite when compared with the unreinforced alloy and were on par with the AA2219 composites containing synthetic reinforcements.

12

Microstructure and Tribological Behavior of Cu-2.5Ti Alloy in Two Different Environments

Efe Ceren, Sun Yavuz, Türen Yunus, Ahlatci Hayrettin

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1443--1453

EN

In this study, the nominal composition of Cu-2.5Ti alloy was thermally treated to obtain homogenized, aged, and 40% prior cold-rolled+ aged samples. The hardness, wear behavior, and microstructure of samples were investigated. The reciprocating wear tests were performed under four different loads under dry and 3.5%NaCl corrosive environments. The alloy reached its highest hardness value of 8 hours for the aged sample. The hardness value of the sample that was homogenized then cold-rolled by 40% and aged was found higher than the other samples. A decrease in the wear rates in dry conditions was observed in homogenized, aged and cold-rolled and aged samples, respectively. This decrease was more in the corrosive environment. Studies can be advanced by examining the wear behavior at different alloy ratios. The effects of different alloying elements and the ratio of cold-rolled before or after aging can also be investigated for future research.

13

Mechanical Behavior of Nitrocarburised Austenitic Steel Coated with N-DLC by Means of DC and Pulsed Glow Discharge

Borowski Tomasz, Kulikowski Krzysztof, Spychalski Maciej, Rożniatowski Krzysztof, Rajchel B., Adamczyk-Cieślak Bogusława, Wierzchoń Tadeusz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

317--324

EN

AISI 316L steel was subjected to nitrocarburizing under glow discharge conditions, which was followed by DLC (diamond-like carbon) coatings deposition using the same device. The coatings were applied under conditions of direct current and pulsed glow discharge. In order to determine the influence of the produced nitrocarbon austenite layer and the type of discharge on the microstructure and mechanical properties of the coatings, the following features were analysed: surface roughness, coating thickness, structure, chemical composition, adhesion and resistance to frictional wear. For comparison purposes, DLC coatings were also deposited on steel without a nitrocarburised layer. The obtained results indicate a significant influence of the type of glow discharge on the roughness, hardness, nitrogen content and of the nitrocarburised layer on the resistance to wear by friction and adhesion of the produced coatings.

14

Investigation of the Microstructure and Strengthening Mechanisms of Ti-6Cu-8Nb-xCr3C2 Alloy through Vacuum Sintering Process

Chang Shih-Hsien, Weng Chen-Yu, Huang Kuo-Tsung, Liang Cheng

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

815--825

EN

This study mixes four different powders to produce Ti-6Cu-8Nb-xCr3C2 (x = 1, 3, and 5 mass%) alloys in three different proportions. The experimental results reveal that when 5 mass% Cr3C2 was added to the Ti-6Cu-8Nb alloys, the specimen possessed optimal mechanical properties after sintering at 1275°C for 1 h. The relative density reached 98.23%, hardness was enhanced to 67.8 HRA, and the transverse rupture strength (TRS) increased to 1821.2 MPa, respectively. The EBSD results show that the added Cr3C2 in situ decomposed into TiC and NbC during the sintering process, and the generated intermetallic compounds (Ti2Cu) were evenly dispersed in the Ti matrix. Furthermore, the reduced Cr atom acts as a β-phase stabilizing element and solid-solution in the Ti matrix. Consequently, the main strengthening mechanisms of the Ti-6Cu-8Nb-xCr3C2 alloys include dispersion strengthening, solid-solution strengthening, and precipitation hardening.

15

Effect of Machining Process Parameters and Number of Pass on Compaction Behaviour of Commercially Pure Aluminium Chips Consolidated by Equal Channel Angular Pressing (ECAP) Using Response Surface Methodology

Palanivel Ramaswamy, Vigneshwaran S., Alshqirate Abedalrzaq, Madhavan R., Venkatachalam P., Laubscher R. F.

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

357--370

EN

This work investigates the compaction behaviour of commercial pure aluminium chips (CP Al) produced during a machining operation and subsequently consolidated by Equal Channel Angular Pressing (ECAP). Empirical models were developed to describe the relative density and hardness of the compacted product of ECAP as functions of the initial machining input parameters including cutting edge angle (CA), depth of cut (DOC) and then the number of consolidation pass during ECAP. The models were developed utilizing response surface methodology (RSM) based on data from a central composite face centred factorial design of experiments approach. The models were then validated by using Analysis of Variance (ANOVA). The effect of input parameters on the relative density and hardness of the ECAP consolidated samples are presented and discussed including details as regards to the mechanical and microstructural properties. An optimum set of input parameters are identified and presented where the best relative density and hardness are demonstrated.

16

Effect of Cryogenic Treatment on Wear Resistance and Microstructure of 42CrMo Steel

Zhang Haidong, Yan Xianguo, Chen Zhi, Zhao Minna, Tang Liang, Gao Yuan, Li Fan, Huang Yao, Li Junji

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 1

127--135

EN

In this work, thermo-mechanically treated 42CrMo steel was subjected to cryogenic treatment conducted by means of orthogonal design method, followed by low-temperature tempering to investigate the effect of different parameters of cryogenic treatment on wear resistance of 42CrMo steel and to optimize parameters of cryogenic treatment for improving wear resistance. The results of hardness test and wear test show that cryogenic treatment significantly improves wear resistance with marginal changes in coefficient of friction and hardness. Specifically, cryogenic temperature has the largest impact on wear resistance of 42CrMo steel, holding time has medium impact, and the parameter of treatment cycles has the least impact. The optimum parameters of cryogenic treatment are -196°C for 12 hours with one cycle for improving wear resistance. The results of scanning electron microscopy (SEM) and X-ray diffractometry (XRD) analysis indicate that marginal changes in hardness and coefficient of friction may be owing to little amount of transformation of retained austenite, and the significant influence of cryogenic treatment on improving wear resistance of 42CrMo steel can be mainly attributed to segregation of carbon atoms promoted by cryogenic treatment resulting in more precipitation of carbides in subsequent tempering.

17

Structure and Properties of the S49 Rail after a Long Term Outdoor Exposure

Konieczny Jarosław, Labisz Krzysztof

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 2

280--290

EN

The subject of the research in this work was the S49 rail made of R260 rail steel (1.0623). The carried out investigations concern microstructure tests and tests of mechanical properties of rails after several years of exposure in the open air without usage. The purpose of the work was to determine on the basis of the results of research the possibilities of using the tested rail for usage and application for the construction of tracks on railway sidings. For investigations there were used diverse techniques reaching such engineering materials investigations like light or scanning electron microscope for microstructure investigations, as well as hardness and microhardness test were performed for determinations of the microstructural changes occurred in the upper area of the rails surface. The microstructure changes concerns especially the ferritic and pearlitic structure and the breaks in the present carbide mesh. During investigations it was found out that the tested railway rails are fully useful for application, after machining to achieve required dimensional parameters. It is also of high importance, of the economical point of view, that their price, also in case of earlier installation of the rails, may be lower than the current price offered on the marked for a entire new product. The price difference reaches dimensions in the range of 5% - 10%.

18

A Comparative Study of Tribological Behavior of Moglice and DK-6(PT) Composites

Pashechko Mykhailo, Ishchenko Аnatoliy, Radionenko Aleksandr, Kindrachuk Myroslav, Tisov Oleksandr

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 1

149--157

EN

Authors have produced new polymer-based composite material DK-6(PT) for substitution of Moglice (Diamant) polymer. We manufactured and used sliding-friction test apparatus (pin-on-disc) capable of testing three specimens simultaneously, much reducing time for the test. The monitoring of the material curing process and the Shore hardness test indicate minor difference from reference material. Measurements were carried out during the curing period, since it is important to know change in this parameter over time. The wear test proved that DK-6(PT) composite in the long-time test has good wear resistance: over 80 km of the friction path, the wear loss of both materials is approximately the same. Furthermore, the friction factor of DK-6(PT) is 5–10% less than that of Moglice. Thus, the studied new polymeric composite may compete with well-known material Moglice and significantly cut the expenses for reconditioning of worn slide ways of metal working equipment.

19

The effect of resistance spot welding parameters on microstructure and strength of DP800 steel joints using response surface methodology

Rajarajan Chakkravarthi, Sonar Tushar, Sivaraj Paramasivam, Raja Selvaraj, Mathiazhagan Nallusamy

Advances in Materials Science

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2022

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Vol. 22, nr 3(73)

53--78

EN

The main objective of this paper is to analyze the direct and interaction effect of resistance spot welding (RSW) parameters on microstructure and strength of DP800 steel joints using response surface methodology (RSM). The DP800 steel sheets were spot welded in straight lap and cross lap joint configuration using RSW. The relationship between the RSW parameters, tensile shear fracture load (TSFL) and nugget zone hardness (NZH) was established employing statistical regression analysis and validated using Analysis of Variance (ANOVA). The DP800 steel joints made using welding current of 5.0 kA, electrode pressure of 4.0 MPa, and welding time of 1.50 s displayed maximum STRAIGHT-TSFL of 21.7 kN, CROSS-TSFL of 17.65 kN, and NZH of 589 HV0.5 respectively.

20

Investigation on the microstructure and mechanical properties of ASTM A131 steel manufactured by different welding methods

Ata Fatih, Calık Adnan, Ucar Nazim

Advances in Materials Science

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2022

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Vol. 22, nr 4(74)

32--40

EN

Welding is an indispensable manufacturing process in the shipbuilding industry. The fierce competition involved often necessitates a cost-effective and reliable welding method. In this study, the weldabilities, microstructures and some mechanical properties of ASTM A131 (Grade A) steel joints fabrication by submerged arc welding (SAW), metal active gas (MAG) welding and plasma arc welding (PAW) have been investigated. The microstructures of the welds were examined by optical microscopy. The mechanical properties of the joints were determined by microhardness measurements, tensile and impact tests. The results showed that tensile strength of the joints reached a tensile strength of up to 462 MPa. The locations of the fractures were always adjacent to the base metal. The Charpy impact energy of the weld metal reached a value of 72.5 J, which was 25 % higher than that of the base metal at 57.7 J. A relatively high hardness of 221 HV was obtained in the PAW method compared to 179 HV in the base metal.