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1

Effect of shells number and machining on selected properties of 3D-printed PLA samples

Kowalska Natalia, Szczygieł Paweł, Skrzyniarz Michał, Błasiak Sławomir

Polimery

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2024

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Vol. 69, nr 3

186--190

EN

Effect of shells number (1–5) on tensile properties of PLA samples printed using the FDM/FFF technique was investigated. The crack surface was also analyzed. The best properties were obtained for 4-shell sample. However, due to the large coefficient of variation (>> 10%) in the case of elongation, 3-shell sample was selected for testing the machining impact. Such a large coefficient of variation can be explained by the presence of voids between the layers. The greater the number of layers, the greater the structure defects. Machining increases surface smoothness while reducing tensile strength and practi¬cally unchanged elongation at break.

PL

Zbadano wpływ liczby warstw (1–5) na właściwości mechaniczne przy rozciąganiu próbek PLA otrzymanych techniką FDM/FFF. Analizie poddano także powierzchnie pęknięć. Najlepsze właściwości uzyskano dla próbki 4-warstwowej. Jednak, ze względu na duży współczynnik zmienności (>> 10%) w przypadku wydłużenia, do badań wpływu obróbki skrawaniem wytypowano próbkę 3-warstwową. Tak duży współczynnik zmienności można wyjaśnić obecnością pustych przestrzeni pomiędzy warstwami. Im większa liczba warstw, tym większe defekty struktury. Obróbka skrawaniem zwiększa gładkość powierzchni przy jednoczesnym zmniejszeniu wytrzymałości na rozciąganie i praktycznie niezmienionym wydłużeniu przy zerwaniu.

2

Fabrication and characterization of a 3D printing filament from polylactic acid and Cryptostegia grandiflora fibers

Udhayakumar A., Mayandi K., Rajini N., Murali M., Mohammad Faruq, Al-Lohedan Hamad A., Krishnan Kumar, Santulli Carlo

Materials Science Poland

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2024

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Vol. 42, No. 4

1--10

EN

Additive manufacturing (AM), i.e., 3D printing, has seen significant growth in recent years in all industries due to its potential advantages, requiring the polymers that are adapted as for melt flow index (MFI) to this use to have adequate tensile strength as well. Hence, in this work, a novel ligno-cellulosic fiber from Cryptostegia grandiflora (CG) and polylactic acid (PLA) were blended to obtain a filament for AM using a twin screw extruder. To determine the filament’s suitability for the 3D printing process, MFI and thermal degradation were examined. In order to identify the distribution and the effect of CG fiber (CGF) filler on the matrix, the filaments were examined using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). CGF powder distribution was observed in the microstructure of the CGF/PLA composite filament. Due to the high compatibility between PLA and CGF, their blending slightly increased the degradation temperature, though did not lead to any crystallinity loss, and the CGF/PLA filament showed 12.5% better tensile characteristics than the pure PLA filament. Based on their performance, the CGF may represent a suitable and compatible filler to improve the properties of the PLA filament for 3D printing applications.

3

The Role of Molybdenum in the Formation of the Microstructure and Properties of Al-Cu Alloys

Stąpór Sylwia, Górny M., Gondek Ł., Gracz B., Kawalec M.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 4

39--48

EN

The subject of the presented research is the influence of molybdenum on selected properties of alloys that are based on the Al-Cu system. It could be observed that the introduction of molybdenum to the multi-component alloy at levels of up to 0.5 wt.% showed increases in the degrees of undercooling ΔT along with the increasing contents of the introduced element. The addition of molybdenum contributed to the reduction of the size of the primary grains of the α(Al) phase. Molybdenum improved the strength of the alloy while achieving elongation at a significant level. This is an element that occurs in the alloy – both in the iron-manganese phases and in the segregates inside the grains. Most of the iron-manganese phases occurred in a more spheroidal form. Additionally, tests were carried out on higher molybdenum content in the alloy. The addition of the tested chemical element at a level of 1 wt.% caused the precipitation of the phases that contained molybdenum, which did not dissolve after heat treatment.

4

Application of Instrumented Indentation Test and Neural Networks to determine the constitutive model of in‑situ austenitic stainless steel components

Ma Quoc-Phu, Basterrech Sebastián, Halama Radim, Omacht Daniel, Měsíček Jakub, Hajnyš Jiří, Platoš Jan, Petrů Jana

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e129, 2024

EN

Over the last few decades, Instrumented Indentation Test (IIT) has evolved into a versatile and convenient method for assessing the mechanical properties of metals. Unlike conventional hardness tests, IIT allows for incremental control of the indenter based on depth or force, enabling the measurement of not only hardness but also tensile properties, fracture toughness, and welding residual stress. Two crucial measures in IIT are the reaction force (F) exerted by the tested material on the indenter and the depth of the indenter (D). Evaluation of the mentioned properties from F-D curves typically involves complex analytical formulas that restricts the application of IIT to a limited group of materials. Moreover, for soft materials, such as austenitic stainless steel SS304L, with excessive pile-up/sink-in behaviors, conducting IIT becomes challenging due to improper evaluation of the imprint depth. In this work, we propose a systematic procedure for replacing complex analytical evaluations of IIT and expensive physical measurements. The proposed approach is based on the well-known potential of Neural Networks (NN) for data-driven modeling. We carried out physical IIT and tensile tests on samples prepared from SS304L. In addition, we generated multiple configurations of material properties and simulated the corresponding number of IITs using Finite Element Method (FEM). The information provided by the physical tests and simulated data from FEM are integrated into an NN, to produce a parametric mapping that can predict the parameters of a constitutive model based on any given F-D curve. Our physical and numerical experiments successfully demonstrate the potential of the proposed approach.

5

Achieving high tensile properties and impact toughness in ultrahigh strength lean alloy steel by quenching and partitioning treatment

Wang Lirong, Liang Yilong, Zhao Fei, Xu Fahong, Lei Lei, Long Shaolei, Yang Ming, Jiang Yun

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 1

art. no. e32, 2024

EN

In this study, a desirable combination of strength, ductility, and toughness in low-carbon 30CrMnSiA steel is achieved by a hierarchical multiphase microstructural architecture subjected to one- and two-step quenching and partitioning (Q&P) processes. The microstructural constituents are studied by EBSD, x-ray diffraction, dilatometry, and TEM. Experimental results show that microstructural refinement occurs in the martensite and bainite at a lower quenching temperature, where more Bain groups form in one close-packed plane group. This causes random distribution between martensite and bainite blocks, enlarging the volume of high-angle grain boundaries. Such refined microstructure, particularly for the increased martensite with higher-density dislocations, causes an increased strength at a decreased quenching temperature. By comparison, increased quenching and partitioning temperature produces more stable film-like retained austenite (RA) and a low dislocation density in martensite/bainite (M/B); thus, it provides better deformation by accommodating with M/B laths and absorbing substantial energy due to the transformation-induced plasticity effect. The lower dislocation density, the higher volume fraction of RA, and the higher HAGBs improve the impact toughness and tensile properties of lean alloy steel through a moderate Q&P process.

6

Surkar Hardik Sanjay, Kumar Amit, Sirohi Sachin, Pandey Shailesh M., Świerczyńska Aleksandra, Fydrych Dariusz, Pandey Chandan

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e109, 2024

EN

Unfavourable operating conditions of equipment in the energy industry resulting from high-temperature loads determine the need to use special materials and technological solutions, including welding procedures. In this article, buttering using IN82 (ERNiCr-3) consumables was proposed as a method to improve the weldability of grade 92 steel joined by the gas tungsten arc welding (GTAW) process with AISI 304L (IN617 filler). The microstructural characterization of samples was carried out using an optical microscope, scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy. The welded joint was further characterized by hardness, tensile (room temperature and at 620 °C temperature) and impact tests. Additionally, the fracture surfaces of tensile and impact tests were studied by SEM. Despite the confirmation of the diffusion of alloying elements and significant changes in their concentration, which indicates the formation of Ti and Nb-rich phases, no welding imperfections were detected and favourable joint structures and acceptable properties were obtained. In particular, this concerns the limitation of the formation of brittle structures and the elimination of the untempered martensitic layer. At the same time, there was a significant decrease in the maximum hardness of heat-affected zone (HAZ) on the grade 92 steel side to a relatively low value of 310 HV, and a minimum tensile strength criterion of 600 MPa was achieved with a simultaneous increase in ductility (35% elongation) of the joint. Comparatively, when compared to a non-buttered welded joint, the joint produced with a buttering layer exhibited an increase in the elongation and impact toughness of the welded joint without any compromise in ultimate tensile strength (Sut). The fracture surface of tensile and impact-tested specimens was also characterized using SEM/EDS. Summarizing all the results, it can be concluded that the proposed GTAW procedure of grade 92 and 304L steels can be used in extreme working conditions, in ultra-supercritical power units or the petrochemical and chemical industries.

7

Ocena wpływu parametrów otrzymywania biokopoli(estro-eterów) na wydajność procesu ich syntezy

Paszkiewicz Sandra, Walkowiak Konrad, Irska Izabela, Piesowicz Elżbieta, Bajor Alicja, Baszak Karolina, Damiri Fouad, Berrada Mohammed

Przemysł Chemiczny

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2023

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T. 102, nr 12

1394--1404

PL

Trzy PHF-blok-PTMO kopoli(estro-etery) oparte na surowcach odnawialnych otrzymano metodą polikondensacji w stanie stopionym w różnych warunkach temperaturowych. Wykazano wpływ parametrów procesu syntezy na wartości granicznej liczby lepkościowej, właściwości mechaniczne i termiczne. Wykazano, że możliwy jest dobór parametrów i warunków syntezy w celu uzyskania odpowiednich właściwości użytkowych materiałów w zależności od potrzeb i przyszłych zastosowań.

EN

Three PHF-block-PTMO copoly(ester-ethers) based on renewable raw materials were synthesized by melt polycondensation at 225-240°C. The effect of synthesis parameters on the limiting viscosity number as well as mech. and thermal properties was detd. In particular, Young modulus, tensile strength, elongation at yield, strength at break, elongation at break, limited viscosity no., density and crystallinity degree of the copolymers were detd. as a function of temp. The copolymer synthesized at 235°C showed the highest limited viscosity no. and thus mol. mass. It exhibited superior mech. properties.

8

The effect of natural fillers on the mechanical properties and flammability of low-density polyethylene

Samujło Bronisław

Polimery

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2023

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Vol. 68, nr 7-8

396--402

EN

The effect of 10-40 wt% natural fillers (pumpkin husks, bean sorting waste, pine sawdust) on the mechanical properties and flammability of LDPE was examined. As the filler content increased, the hardness slightly increased and the tensile strength and relative elongation decreased. The tensile modulus more than doubled (pumpkin husks, pine sawdust). The linear combustion rate increased unfavorably, but the assumed flammability class HB40 was achieved, except for LDPE filled with 40 wt% pine sawdust (HB75). At the same time, the temperature in the combustion area decreased in the vertical flammability test.

PL

Zbadano wpływ naturalnych napełniaczy (łuski dyni, odpady sortownicze fasoli, trociny sosnowe) stosowanych w ilości 10-40% mas. na właściwości mechaniczne i palność LDPE. Wraz ze wzrostem zawartości napełniacza nieznacznie zwiększała się twardość, a zmniejszała wytrzymałość na rozciąganie i wydłużenie względne. Moduł sprężystości przy rozciąganiu zwiększył się ponad dwukrotnie (łuski dyni, trociny sosnowe). Niekorzystnie wzrosła liniowa szybkość spalania, ale uzyskano zakładaną klasę palności HB40, poza LDPE z dodatkiem 40% mas. trocin sosnowych (HB75). Jednocześnie obniżyła się temperatura w obszarze spalania w pionowym teście palności.

9

Research on the Knittability of Metallic Yarns in the Warp-knitted Mesh of a Deployable Antenna

Haiyan Xu, Nanliang Chen, Jinhua Jiang

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 2

51--55

EN

Metallic yarns are difficult to be knitted. To resolve the problem, the paper used the knitted yarn strength utilization factor to quantitatively characterize knittability, which was the ratio of yarn strength after being knitted to that of the original yarns. Furthermore, the relationship between the yarns’ basic mechanical properties and the knitted yarn strength utilization factor was investigated by testing the yarns’ basic mechanical properties. The results showed that it was feasible to quantitatively characterize the yarns’ knittability using the knitted yarn strength utilization factor. And also the breaking strength of yarn was not correlated with the knittability. The elongation at break of the yarn was positively correlated with knittability. The bending stiffness of the yarn was negatively correlated with the knittability. Finally, a multiple linear regression model of the knittability and the mechanical properties of the yarn was developed. The model showed that there was a significant linear relationship between knittability and the elongation of yarns at break and the bending rigidity of yarns, with the bending stiffness of yarns being more significant.

10

The Effects of Friction Stir Welding Parameters on Microstructure, Fatigue Life and Tensile Properties of Aluminum 2024-T3 Alloy

Şık Aydın, Özer Alpay

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

499--505

EN

In this study, Al 2024-T3 alloy plates were joined by using friction stir welding. Welding was performed at a rotational speed of 930, 1450, 2280 rpm and a welding feed rate of 180 mm min-1. The welded samples were analyzed at the microstructural level. Moreover, both bending fatigue tests and tensile tests were performed on samples. At the end of the microstructural examination of the samples welded at the rotational speed of 930 rpm and the welding feed rate of 180 mm min-1, the formation of tunnel defects was observed. The highest fatigue life was obtained at 2280 rpm and 180 mm min-1. The lowest fatigue life was obtained at 930 rpm and 180 mm min -1. The highest ultimate tensile stress was obtained at 2280 rpm/180 mm min-1 sample, which shows about a 12% reduction relative to the base material. The lowest ultimate tensile stress was obtained at 930 rpm/180 mm min-1 sample. The ultimate tensile stress value of the 930 rpm/180 mm min-1 sample decreased by approximately 25%.

11

Study on Tensile Properties and Microstructures of Different Sites in Al-Si Alloy Casting Component

Tao Jianquan, Xiang Lin, Chen Xidong, Sun Jipeng, Wang Yanbin, Du Chuanhang, Peng Feifei, Gao Shiqing, Chen Qiang

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

585--589

EN

The tensile properties and microstructures of ZL114A alloy component with a complex shape are investigated at room temperature and 200°C, using the tensile tests, scanning electron microscopy and electron backscattering diffraction. Both thin wall and thick structure exhibit excellent properties, of which max ultimate tensile strength and elongation at break reach 314 MPa and 2.5% at room temperature, respectively. The ultimate tensile strengths of thin wall are 40 MPa and 25 MPa greater than those of thick structure at room temperature and 200°C, respectively. Moreover, the eutectic Si phases of thin wall exhibit a predominantly spherical morphology while of the morphology of thick structure are rod-like, resulting in the different mechanical properties between thin wall and thick structure. The fracture morphologies of thin wall and thick structure are studied to explain the difference in performance between thin wall and thick structure.

12

Effects of SPD by Biaxial Alternate Forging on the Tensile Properties and Microstructure of AZ31B Magnesium Alloy

Shin Young-Chul, Ha Seong-Ho, Shah Abdul Wahid

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

97--101

EN

The forming limit of AZ31 alloy, a representative Mg-Al-Zn-based wrought alloy, and the effect of severe plastic deformation (SPD) by examining the microstructure change caused by dynamic recrystallization led by high temperature and high dislocation density at 300℃ using a biaxial alternate forging (BAF) were investigated in this study. As a result of BAF test for AZ31 Mg alloy, significant cracks on the ends of workpieces occurred after 7 passes. The microstructure of as-extruded specimen showed the non-uniform distribution of the relatively coarse grains and the fine grains considered to be sub-grains. However, as the number of passes increases, the area of coarse grains gradually disappeared and the fine grains became more dominant in the microstructures. The result of tensile test for workpieces with each forging pass showed an increase in strength depending on pass number was shown with a slight increase of elongation. The Electron Backscatter Diffraction (EBSD) results exhibited that, the microstructure showed the presence of coarse grains and twins after only 1 pass, while the grains appeared to be significantly refined and uniformly distributed after 3 pass, at which the strength and elongation began to increase, simultaneously.

13

Influence of Rare Earth Sm Addition on Microstructure and Tensile Properties of Al-Si-Cu 319 Alloy

Patel D. N., Sutaria Mayur P.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

25--33

EN

In the present investigation, the influence of addition of the rare earth element samarium (Sm) in different concentrations (0, 0.1, 0.3, 0.5, 0.7 and 0.9wt.%) on the microstructure and tensile properties of the Al-Si-Cu 319 alloy have been evaluated. Microstructural constituents such as SDAS of α-Al and characteristics of eutectic silicon particles were observed by optical microscopy. It was concluded from the findings that Sm addition reduces the size of secondary dendrite arm spacings (SDAS) and altered the morphology of the eutectic silicon particles from needle-like to lamellar and smaller segments. The tensile properties of the Al-Si-Cu 319 alloy improved with the concentration of Sm. It was found that the highest tensile properties were obtained at 0.7wt.% addition of Sm, i.e., 55.5% higher than unmodified 319 alloy. With the further addition of the Sm above 0.7wt.%, it does not improve the tensile properties of the alloy. This can be attributed to the precipitation of the brittle and needle like quaternary Sm-rich intermetallic compounds observed through Scanning electron microscopy.

14

Comparison of Tensile Properties of Nb Grain Refined A206 Alloy by Gravity and Tilt Casting

Palamutcu Nuri, Dizdar Kerem Can, Sahin Hayati, Dispinar Derya

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

49--53

EN

Turbulent filling of a mould is one of the ways to introduce extrinsic defects into the cast part that could deteriorate many properties of any casting. The turbulence can be easily eliminated by counter gravity casting. In gravity casting, tapered downsprue, tapered runner is needed such that the mould cavity is filled counter-gravity from the bottom which is the only best way to eliminate turbulence during filling. Tilt casting method also exists which has the potential to quiescently transfer the liquid into the mould cavity. In this work, gravity and tilt casting methods were used to evaluate the tensile properties of Nb grain refined 206 alloy. Three different Nb contents were investigated: 0.025, 0.05 and 0.1 wt% ratios and it was found that 0.05 wt% revealed the highest tensile properties. On the other hand, when the intrusion of surface folded oxides was eliminated during filling, it was found that mechanical properties were increased significantly, and particularly, the toughness was increased by two folds when tilt casting was applied compared to gravity casting.

15

Reinforcement of compatibilized nanoclay/Inviya fibers to epoxy‑based glass fiber nanocomposites for high‑impact strength applications

Shelly Daksh, Nanda Tarun, Mehta Rajeev

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e84, 2023

EN

This research work is the first successful trial in which silanized nanoclay and compatibilized Inviya fibers were reinforced in epoxy-based glass fiber reinforced composites (EGFCs) resulting in significant improvements in impact strength without degrading tensile properties. Vacuum assisted resin infusion moulding (VARIM) technique was used for processing of multi-scale filler reinforced EGFCs. Inviya fibers were used, because of their high ‘elastic recovery’ and ‘stretchability’ (five times the original length) due to alternative flexible and rigid molecular structure. Nanoclay and Inviya fibers were subjected to compatibilization with different surface treatments. Compatibilization of fillers was confirmed through Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy-Energy-dispersive spectroscopy (FE-SEM/EDS) analysis. Nanoclay dispersion and morphology in EGFCs was ascertained through X-ray diffraction (XRD) and Transmission electron microscopy (TEM) analysis. Reinforcement of compatibilized Inviya fibres (First Method: maleic anhydride grafting, and Second Method: combination of phosphoric acid treatment followed by silanization) enhanced the impact strength by 132% and 150%, respectively, over the reference composition. FE-SEM micrographs of fracture surface of impact test specimens were utilized to identify the mechanisms causing improvement in impact behaviour.

16

Recent developments in pullout behaviors and tensile properties of ultra-high-performance concrete reinforced with steel fiber

Wu Hansong, Zang Zhishu, Deng Shiyi, Shen Aiqin, Cai Yanxia, Ren Guiping, Pan Hongmei

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e216, 2023

EN

Ultra-high-performance concrete (UHPC) has gained significant attention as a construction material owing to its exceptional mechanical properties and durability. Steel fibers are widely utilized as a reinforcement material for UHPC. Achieving excellent bond and tensile performances is considered to be a predominant issue for the utilization of steel fiber reinforcement. This comprehensive review presents recent research progress on the bond and tensile properties of steel-fiber-reinforced UHPC. First, an overview of the experimental methods for evaluating pullout and tensile performance is provided. Subsequently, the factors influencing these properties are discussed in detail. The review then comprehensively examines several analytical models for steel-fiber-reinforced UHPC, ranging from traditional approaches to innovative methods such as artificial neural network models, genetic algorithms, deep learning methods, inverse analysis, and micromechanical damage models. Furthermore, the correlations between pullout behavior, tensile performance, and flexural strength are explored in detail. Finally, the review addresses essential considerations and summarizes various modification techniques for improving the pullout and tensile performances, including physical and chemical methods of modifying the steel fiber surface and UHPC matrix. This review serves as a valuable reference for researchers and engineers in relevant fields, promoting further research and application of steel fiber-reinforced UHPC.

17

The effect of basalt knitted fabric on the properties of green epoxy resin

Jamshaid Hafsa, Rajput Abdul Waqar, Zahid Bilal, Memon Sanam, Qureshi Raja Fahad, Aslam Sarmad, Nadeem Muhammad

Polimery

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2022

|

Vol. 67, nr 2

67--71

EN

The influence of basalt fabric on the tensile mechanical properties and the impact resistance of green epoxy resin was investigated. Composites with parallel arrangement of insert yarns had better properties than in the case of their perpendicular arrangement. The properties were also influenced by the number of layers of the fabric. The tensile strength and impact resistance of the composites were better than the commercially available side mirror covers due to the superior properties of the basalt fiber.

PL

Zbadano wpływ tkaniny bazaltowej na właściwości mechaniczne przy rozciąganiu i odporność na uderzenie „zielonej” żywicy epoksydowej. Kompozyty o równoległym ułożeniu przędzy charakteryzowały się lepszymi właściwościami niż te o prostopadłym ułożeniu. Na właściwości miała również wpływ liczba warstw tkaniny. Wytrzymałość na rozciąganie i odporność na uderzenie kompozytów były lepsze niż dostępnych na rynku osłon lusterek bocznych ze względu na dobre właściwości włókna bazaltowego.

18

Comparative analysis of cold and warm rolling on tensile properties and microstructure of additive manufactured Inconel 718

Zhang Tao, Li Huigui, Gong Hai, Wu Yunxin, Ahmad Abdulrahaman Shuaibu, Chen Xin, Zhang Xiaoyong

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e44, 2022

EN

Despite the high efficiency and low cost of wire + arc additive manufacture (WAAM), the epitaxial grown columnar dendrites of WAAM deposited Inconel 718 cause inferior properties and severe anisotropy compared to the wrought components. Fundamental studies on the influence of one-pass cold and warm rolling on hardness and microstructure were investigated. Then the interpass cold and warm rolling on tensile properties were also analyzed. The results show that the one-pass rolling increases the hardness and displays a heterogeneous hardness distribution compared to the as-deposited material, and the warm rolling exhibits a larger and deeper strain compared to cold rolling. The columnar dendrites gradually change to cell dendrites under the rolling process and then change to equiaxed grains with the subsequent new layer deposition. The average grain size is 16.8 μm and 23.5 μm for the warm and cold rolling, respectively. The strongly textured columnar dendrites with preferred < 001 > orientation transform to equiaxed grains with random orientation after rolling process. The grain refinement contributes to the dispersive distributed strengthening phases and the increase in its fraction with heat treatment. The as-deposited samples show superior tensile properties compared to the cast material but inferior compared to the wrought components, while the warm-rolled samples show superior tensile properties to wrought material. Isotropic tensile properties are obtained in warm rolling compared to cold rolling. The rolling process and heat treatment both decrease the elongation and lead to a transgranular ductile fracture mode. Finally, the rolling-induced strengthening mechanism was discussed.

19

Effect of heat treatment on the tensile properties of incrementally processed modified polylactide

Kozik Bogdan, Dębski Mariusz, Bąk Piotr, Gontarz Małgorzata, Zaborniak Małgorzata

Polimery

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2021

|

T. 66, nr 6

357--361

EN

The influence of temperature (80, 95 and 110°C) and annealing time (20, 25, 30 min) on the tensile strength and elongation at break of the modified polylactide (PLA Pro) processed by 3D printing (FFF – Fused Filament Fabrication) was investigated. The properties of PLA Pro were compared with properties of unmodified PLA and ABS. It was observed that the tensile strength was comparable for all annealed samples and was about 45 MPa. Moreover, the annealing process decreased the tensile strength of the modified PLA and increased the elongation at break, which may be related to a change in the degree of crystallinity. The modified PLA was characterized by tensile properties similar to ABS.

PL

Zbadano wpływ temperatury (80, 95 i 110°C) i czasu wygrzewania (20, 25, 30 min) na wytrzymałość na rozciąganie i wydłużenie względne przy zerwaniu modyfikowanego polilaktydu (PLA Pro) przetwarzanego metodą druku 3D (FFF – Fused Filament Fabrication). Właściwości PLA Pro porównano z właściwościami niemodyfikowanego PLA i ABS. Zaobserwowano, że wytrzymałość na rozciąganie była porównywalna dla wszystkich próbek i wynosiła około 45 MPa. Ponadto, proces wygrzewania spowodował zmniejszenie wytrzymałości na rozciąganie modyfikowanego PLA i zwiększył wydłużenie przy zerwaniu, co może być związane ze zmianą stopnia krystaliczności. Modyfikowany PLA charakteryzował się właściwościami mechanicznymi przy rozciąganiu podobnymi do ABS.

20

Application of Artificial Neural Network to Predict the Tensile Properties of Dual-Phase Steels

Shin Seung-Hyeok, Kim Sang-Gyu, Hwang Byoungchul

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

719--723

EN

An artificial neural network (ANN) model was developed to predict the tensile properties of dual-phase steels in terms of alloying elements and microstructural factors. The developed ANN model was confirmed to be more reasonable than the multiple linear regression model to predict the tensile properties. In addition, the 3D contour maps and an average index of the relative importance calculated by the developed ANN model, demonstrated the importance of controlling microstructural factors to achieve the required tensile properties of the dual-phase steels. The ANN model is expected to be useful in understanding the complex relationship between alloying elements, microstructural factors, and tensile properties in dual-phase steels.