Materialwissenschaft und Werkstofftechnik最新文献

Commercially pure titanium-grade 2 tube was fabricated using gas tungsten arc welding, which yielded perfect welds suitable for usage in several industries. Through conducting extensive testing and determining the optimal process parameters, this approach was optimized. The welded microstructure of the material was analyzed using optical microscopy which revealed columnar and equiaxed dendrites that were primarily composed of α and β-Titanium phases. These microstructural modifications, the product of constitutional supercooling and thermal histories, have significantly improved the mechanical properties of the welded pipe. The tensile strength increased by 3 % to 360.52 MPa ±2.5 MPa, while the strength of the base metal was 350.01 MPa ±2.5 MPa. Significantly, the welded pipe outperformed the base metal in terms of mechanical strength, and a 180° bend test demonstrated its ductility by obviating any signs of fracture. Microhardness evaluations showed that the weld metal had maximum values (172 HV 0.5 to 195 HV 0.5) while the base metal area had lower values (150 HV 0.5 to 157 HV 0.5). This in-depth examination demonstrates potential of commercially pure titanium-grade 2 for a range of industrial uses and offers insight into effective production of the material via gas tungsten arc welding.

A zirconium-based alloy called zircaloy-2 is well known for its exceptional resistance to corrosion and low cross-sectional absorption of neutrons, which makes it a vital component for fuel cladding application in the nuclear industry. Tungsten inert gas welding is an effective method for joining zircaloy due to its precise heat control and inert gas shielding, ensuring high-quality welds with minimal contamination. This technique is particularly advantageous for applications demanding excellent corrosion resistance and mechanical properties. Fabrication of zircaloy-2 sheets through tungsten inert gas welding, guided by optimal process parameters derived from extensive trial-and-error testing, has yielded welds with impeccable quality suitable for deployment in nuclear, aerospace, and marine sectors. Analysis of welded microstructure of material revealed the presence of columnar and equiaxed dendrites near the weld metal, primarily composed of α-zirconium and β-zirconium phases, as evidenced by optical microscopy and x-ray diffraction. These microstructural variations, induced by constitutional supercooling and thermal histories, have significantly enhanced the mechanical properties of welded pipe. There is an increase of 4.3 % in strength as tensile strength of 477 MPa, while base metal exhibited strength of 457 MPa. Notably, the welded sheet exhibited superior mechanical strength compared to the base metal, with ductility demonstrated through a 180° bend test showing no signs of cracking proving its ductility. Microhardness assessments highlighted a decline in hardness within the base metal region (178 HV 0.5 to 186 HV 0.5), contrasting with peak values observed in the weld metal (215 HV 0.5 to 223 HV 0.5). This comprehensive investigation sheds light on the successful fabrication of zircaloy-2 via tungsten inert gas welding, emphasizing its potential for diverse industrial application.

The microstructure and properties of the Cu-12Sn-4Ni alloy were analyzed by incorporating varying amounts of the rare earth element cerium. The study compared the alloy‘s microstructure, hardness, strength, friction, and wear. The results showed that adding 0.04 % of rare earth cerium refined the grain size of the Cu-12Sn-4Ni alloy from 75 μm to 200 μm to 75 μm to125 μm. The hardness of the alloy increased by 22.78 % to 135.897 HV 0.1 after adding cerium, and the tensile strength of the alloy reached its highest peak at 452.08 MPa, with an elongation of up to 64.735 % after fracture. Additionally, the wear rate of the material decreased by about 38.6 % to 1.61×10⁻⁵ mm³/mm. In conclusion, the addition of the rare-earth element cerium successfully improved the structure and properties of the Cu-12Sn-4Ni alloy, leading to enhanced hardness, strength, and wear resistance.

This study investigates the enhancement of wear and friction performance in an AA 5083 matrix composite by incorporating copper ferrite (CuFe₂O₄) micro and nanoparticles, synthesized through a green process using mulberry (Morus alba L.) leaf extract for the first time. Two distinct composites are fabricated using the liquid metallurgy vortex-route method featuring an aluminum AA 5083 matrix and 0.2 % micro- and nano- copper ferrite reinforcement by weight. AA 5083 cast alloy under identical conditions. Characterization analyses were conducted to elucidate the composite properties. The composite samples are underwent wear tests against a steel disc under three different loads (10 N, 20 N, and 40 N) at two sliding distances (250 m and 500 m), maintaining a constant sliding speed of 2.6 m/s using a pin-on-disc wear test apparatus. The composites exhibited superior wear and friction performance compared to the unreinforced material. Overall, the nano-copper ferrite reinforced material showcased, on average, 33 % and 52 % lower wear rates than the unreinforced material, and 27 % and 31 % lower wear rates than the micro-copper ferrite reinforced material respectively.

High iron-containing cast aluminum-silicon-magnesium alloys have been developed for utilization recycled aluminum alloys. Iron-containing intermetallic compounds (IMCs) are commonly considered as harmful to mechanical properties in the cast aluminum alloys containing Fe impurities. Friction stir welding (FSW) is applied to weld butt joint between cast aluminum-silicon-magnesium-iron alloys plates with 1 wt.-%, 2 wt.-% and 4 wt.-% Fe contents. Iron-containing intermetallic compounds become finely fragmented and distributed in the aluminum matrix by friction stir welding. Friction stir welding clearly improves mechanical properties of the joints over the base materials. Fragmented intermetallic compounds in high iron-containing aluminum-silicon-magnesium alloys can enhance tensile strength over the commercial A356 aluminum alloy.

In this paper, the additives consisting of bis-(3-sulfopropyl)-disulfide, hydroxyethylcellulose and collagen additive compounding are used to fabricate ultra-thin copper foils with low roughness on titanium substrates. The results show that the deposited layers obtained at the electrodeposition time of 3 min, the electrolyte temperature of 50 °C and the output voltage of 2.5 V exhibit small grain size and good adhesion to the substrate. Meanwhile, the effects of the two-component additive and the three-component additive on the microstructures, surface roughness and electrochemical behavior of copper foils are studied. The x-ray diffraction results reveal that copper foils prepared by simultaneous introduction of 0.06 g/L bis-(3-sulfopropyl)-disulfide and 0.08 g/L collagen possess a dense and homogeneous structure with the smallest grain size and the lowest roughness, which is diminished by 26.17 %. The electrochemical results indicated that the SC additive had an inhibitory effect on the deposition of copper ions, while the SH additive exerted depolarizing effect in this electrolyte system, accelerating the deposition of copper particles, which was attributed to the antagonistic interaction between bis-(3-sulfopropyl)-disulfide and hydroxyethylcellulose that hindered the preferential adsorption of the additive at the surface protrusions, resulting in the decrease in the refinement effect of the bis-(3-sulfopropyl)-disulfide additive. Under the optimized process parameters, the increase in the deposition rate of Cu²⁺ balances the relationship between nucleation and growth of copper ions, which ultimately produces the copper foil with smooth surface and low roughness.

FeSiAl/SrFe₁₂O₁₉ soft magnetic composite material was prepared by mechanically crushing FeSiAl powder and M-type permanent magnet hexagonal ferrite powder according to a certain quality. Their structures, morphologies, and magnetic properties were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), SQUID, and B−H analyzers. Compared to organic and other inorganic composite materials, SrFe₁₂O₁₉ has a higher thermal decomposition temperature. The x-ray diffraction pattern indicates that SrFe₁₂O₁₉ phase was detected in the sample. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) images show that powdered SrFe₁₂O₁₉ is dispersed on the surfaces and gaps of particles of different sizes. The magnetic analysis results indicate that although SrFe₁₂O₁₉ increases the hysteresis loss of the material, its good insulation reduces eddy current loss. When the content of SrFe₁₂O₁₉ is 2 wt.-%, the magnetic loss is the lowest. The lower magnetic loss and higher thermal decomposition temperature of this composite material make it have a wider range of application prospects.