In this study, microstructural characterization, mechanical (tensile and compressive) properties, and tribological (wear) properties of Titanium Grade 5 alloy after the oxidation process were ...examined. While it is observed that the grey contrast coloured α grains are coaxial in the microstructures, it is seen that there are black contrast coloured β grains at the grain boundaries. However, in oxidised Titanium Grade 5, it is possible to observe that the α structure becomes larger, and the number and density of the structure increases. Small-sized structures can be seen inside the growing α particles and on the β particles. These structures are predicted to be Al-Ti/Al-V secondary phases. The nonoxidised alloy matrix and the OL layer exhibited a macrolevel hardness of 335 ± 3.21 HB and 353 ± 1.62 HB, respectively. The heat treatment increased Vickers microhardness by 13% in polished and etched nonoxidised and oxidised alloys, from 309 ± 2.08 HV1 to 352 ± 1.43 HV1. The Vickers microhardness value of the oxidised sample was 528 ± 1.74 HV1, as a 50% increase was noted. According to their tensile properties, oxidised alloys showed a better result compared to nonoxidised alloys. While the peak stress in the oxidised alloy was 1028.40 MPa, in the nonoxidised alloy, this value was 1027.20 MPa. It is seen that the peak stresses of both materials are close to each other, and the result of the oxidised alloy is slightly better. When we look at the breaking strain to characterise the deformation behaviour in the materials, it is 0.084 mm/mm in the oxidised alloy; In the nonoxidised alloy, it is 0.066 mm/mm. When we look at the stress at offset yield of the two alloys, it is 694.56 MPa in the oxidised alloy; it was found to be 674.092 MPa in the nonoxidised alloy. According to their compressive test properties, the maximum compressive strength is 2164.32 MPa in the oxidised alloy; in the nonoxidised alloy, it is 1531.52 MPa. While the yield strength is 972.50 MPa in oxidised Titanium Grade 5, it was found to be 934.16 MPa in nonoxidised Titanium Grade 5. When the compressive deformation oxidised alloy is 100.01%, in the nonoxidised alloy, it is 68.50%. According to their tribological properties, the oxidised alloy provided the least weight loss after 10,000 m and had the best wear resistance. This material's weight loss and wear coefficient at the end of 10,000 m are 0.127 ± 0.0002 g and (63.45 ± 0.15) × 10
g/Nm, respectively. The highest weight loss and worst wear resistance have been observed in the nonoxidised alloy. The weight loss and wear coefficients at the end of 10,000 m are 0.140 ± 0.0003 g and (69.75 ± 0.09) × 10
g/Nm, respectively. The oxidation process has been shown to improve the tribological properties of Titanium Grade 5 alloy.
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Microstructure, mechanical properties and corrosion resistance of as-cast and as-extruded Mg–4 wt% Zn–1 wt% La magnesium alloys were investigated. The alloys were produced by low-pressure die casting ...method and extruded at 350 °C after homogenization at 400 °C for 24 h. The results show that the as-cast alloy mainly consists of primary α-Mg matrix and Mg–Zn–La ternary second phases (also called T-Phase) along grain boundaries and isolated spherical particles inside the grains. After extrusion at 350 °C, the average grain size decreases by 81% due to dynamic recrystallization mechanism and T-phase particles are distributed along the extrusion direction. The elongation, yield strength and tensile strength of the as-cast Mg–4Zn–1La alloy increase by 179%, 90% and 40%, respectively, as a result of the extrusion process. The as-extruded Mg–4Zn–1La alloy shows better corrosion resistance than the as-cast alloy due to increased grain boundaries and decreased content of T-phase.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this study, the microstructural properties, wear resistance, and corrosion behavior of H111 hot-rolled AA5754 alloy before heat treatment, after homogenization, and after aging were examined. The ...microstructure was mainly composed of the scattered forms of black and gray contrast particles on the matrix and precipitations were observed at the boundaries of the grain. The as-rolled material exhibited a dense pancake-shaped grain structure, which is typical of as-rolled material. Observation along the L-direction did not yield distinct demarcations among the grains and was not uniformly distributed, with precipitates at the grain boundary. When they aged, there was a parallel increase in fine and huge black and gray contrast particles in the zone. Therefore, it could be stated that the amount of fine grains increased due to the rise in the homogenization process. The rolled base metal with the grain orientation was found to be parallel to the rolling direction. On the other hand, the coarse grains were clearly observed in the aging heat-treatment condition. The grains had an elongated morphology consistent with the rolling process of the metal before the heat-treatment process. The aged alloy had the highest hardness with a value of 86.83 HB; the lowest hardness was seen in the alloy before heat treatment with a value of 68.67 HB. The weight loss and wear rate of this material at the end of 10,000 m were, respectively, 1.01 × 10−3 g and 5.07 × 10−9 g/Nm. It was observed that the alloy had the highest weight loss and worst wear resistance before heat treatment. Weight loss and wear rates at the end of 10,000 m were, respectively, 3.42 × 10−3 g and 17.08 × 10−9 g/Nm. According to these results, the friction coefficients during wear were parallel and the material with the lowest friction coefficient after aging was 0.045. While the alloys corroded after aging showed more weight loss, the alloys corroded before heat treatment exhibited better corrosion behavior. Among the alloys, the least weight loss after 24 h was observed in the alloy that was corroded before heat treatment and this value was 0.69 × 10−3 mg/dm2. The highest weight loss was observed in the aged alloy with a value of 1.37 × 10−3 mg/dm2. The alloy before heat treatment, which corroded after casting, showed the lowest corrosion rate with a value of 0.39 × 10−3 mg/(dm2·day) after 72 h. The alloy that was corroded before heat treatment showed the best corrosion behavior by creating a corrosion potential of 1.04 ± 1.5 V at a current density of −586 ± 0.04 μA/cm2. However, after aging, the corroded alloy showed the worst corrosion behavior with a corrosion potential of 5.16 ± 3.3 V at a current density of −880 ± 0.01 μA/cm2.
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In this study, an Al5083-H111 alloy was divided into two different parameters without heat treatment and by applying homogenization heat treatment. In the homogenized Al5083 sample, it helped to make ...the matrix structure more homogeneous and refined and distribute intermetallic phases, such as the Al-Mg phase (Mg2Al3) and Al-Fe phases, more evenly in the matrix. There was an increase in the hardness of the homogenized sample. The increase in hardness is due to the material having a more homogeneous structure. Corrosion tests were applied to these parameters in NaCl and NaOH. It is observed that Al5083 samples before and after heat treatment show better corrosion resistance and less weight loss in NaOH and NaCl environments. It was observed that the fracture resistance of the alloy in the NaOH solution was lower, and the weight loss was higher than the alloy in the NaCl solution. Wear tests were performed on two different parameters: a dry environment and a NaOH solution. Since the NaOH solution has a lubricating effect on the wear surface of the sample and increases the corrosion resistance of the oxide layers formed, the wear resistance of the alloys in dry environments was lower than the wear resistance of the alloys in the NaOH solution. A hydrogen evolution test was performed on the samples in the NaOH solution, and the results were recorded. Hydrogen production showed higher hydrogen output from the homogenized sample. Accordingly, a higher corrosion rate was observed.
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In this study, Mg-0.5Ca alloy was produced in a newly designed unit during
the metal injection molding process. 40?mD90 Mg powder and 500nmD90 Ca
powder were used in accordance with injection molding ...and powder sintering
rules. In the injection phase, Polyethylene-glycol (PEG) and
Poly-methyl-methacrylate (PMMA) and stearic acid (SA) polymers act as
binders and lubricants. In the experimental phase, X-ray Diffractometer
(XRD), Thermal Gravimetric Analyze (TGA), Scanning Electron Microscope (SEM)
equipped with Energy Dispersive Spectroscopy Mapping (EDS and MAP), and
Vickers microhardness (HV) examinations were performed. The samples produced
were subjected to the sintering process at different temperatures and times.
Conventional powder sinter stages point, neck, and joining structures were
obtained at different temperatures and durations. As a result, it was
determined that Mg-0.5Ca alloy reached a metallic form with the specified
polymer structure only at 600oC temperature and after 5 h sintering. Grain
boundaries were formed in the sintered sample and the presence of the Mg2Ca
phase was observed. The hardness of the metallic structure obtained was
measured as 49.9 HV0.1 on average.
•Mg is the lightest metal used in structural applications.•The most important disadvantages of Mg alloys are their low strength and wear resistance.•Different ratios of Pb were added to alloys ...reinforced with Mg2Si particles.•According to wear tests, wear resistance decreased with the addition of Pb.
In this study, the effect of adding Pb at different ratios on the wear resistance of Mg alloys reinforced with low density “in situ” Mg2Si particles has been investigated. Pb, at a rate of 0.2%, 0.5%, and 1%, was added to Mg–10% Al–12Si alloys reinforced with “in situ” particles, produced from the reinforcement nucleation within the matrix. The microstructure characterisation and wear properties of alloys, produced using a casting method was examined. Light Optical Microscopy (LOM), X-ray Diffraction (XRD) analyses and a Scanning Electron Microscope (SEM) were used to conduct the microstructure characterisation. A pin-on-disc type wear device, under different loads and different sliding distances, was used to conduct the dry environment wear experiments carried out for investigated alloys. Microstructure analysis concluded that Mg2Si particles formed, and that an Mg17Al12 intermetallic phase was present in the structure. The Pb added to the alloys decreased the wear resistance of the alloy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Contrary to previous studies, examinations were carried out on the undamaged material.•Mechanical strength of draw hook investigated using experimental and numerical methods.•The draw hook sample ...met standards to high cycle and low cycle fatigue.•Mechanical properties were interpreted through metallurgical characterization.
The coupling set, exposed to multi-directional severe dynamic loads, is a vital part that connects the wagons in rail system vehicles. These loads are usually transferred through the hook body in the draw hook coupler variant. Recently, some researchers have suggested that draw hook equipment suffers from fatigue damage if periodic maintenance is not performed correctly. For this reason, transportation safety is in danger. This study investigated fatigue occurring in the draw hook body and other metallurgical and mechanical properties affecting fatigue experimentally and numerically. The microstructure characterisation of the material was made using optic microscopy, electron spectrometry and scanning electron microscopes. The Brinell hardness and tensile test examined the material's mechanical properties. The fatigue behaviour rotating bending test and the complex S-N curves were obtained. For the computer validation of fatigue behaviour, stress life and strain life fatigue analyses were carried out using a commercial ANSYS program package. The high and low cycle fatigue regions are highlighted in the S-N curves. The endurance limit for the stress of 424.6 MPa was determined at 1.3 × 107 cycles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, microstructure, mechanical, corrosion and corrosive wear properties of Mg-xAg the as-cast and extruded alloys (x: 1, 3 and 5 wt. % Ag) were investigated. According to the experimental ...results, as the amount of Ag added in the casting alloys increases, the secondary phases (Mg4Ag, Mg54Ag17) emerging in the structure have become more clarified. Furthermore, it was observed that as the amount of Ag increased, the grain size decreased and thus the mechanical properties of the alloys increased. Similarly, the extrusion process enabled the grains to be refined and the mechanical properties to be increased. As a result of the in vitro tests performed, the Mg-1Ag exhibited very bad corrosion properties compared to other alloys. On the other hand, according to corrosive wear tests results, a high wear rate and friction coefficient were found for Mg-5Ag alloys.
The wear resistance of sheet magnesium alloy AZ31 (Mg – 2.90% Al – 0.98% Zn – 0.13% Mn) with microarc oxidation coatings after shot peening is determined. The microstructure of the alloy is studied ...by scanning electron microscopy. The effect of the shot peening on formation of cracks and pores in the alloy after microarc oxidation and on the roughness of the surface is determined in order to predict the wear resistance of the alloy under dry friction.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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.
