5052H34 Al-Mg plates were annealed and then friction stir processed at various rotation speeds ranging from 500 to 1500 rpm to investigate the tensile properties and vibration fracture resistance. The experimental results indicate that grain refinement could be observed at the stir zone with an average grain size varying from 5–16 μm. Based on the observed microstructure and tensile deformation resistance data, the k_y slope value of the Hall-Petch equation can be determined. A refined grain size in the stir zone is a common feature of the friction stirred specimens. Different rotation speeds have different corresponding grain sizes and this can be attributed to dynamic recrystallization during friction stir processing (FSP). The effect of grain size on vibration fracture resistance in the stir zone was also examined. Results show that the vibration fracture resistance of the stir zone decreases with increasing the rotation speed. An increase in grain size due to higher rotation speed is detrimental to the vibration propagation resistance, and a small variation in grain size can result in significant changes in the duration of stage I of the D-N curves. The inward crack propagation behavior was found to be the main controlling factor on vibration fracture resistance. This result agrees with the variation in crack propagation rate.

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The distribution of the temperature was estimated by combination of electrical and thermal calculations on the basis of Ohm’s and Fourier’s laws in the fuse element-connector-electric wire system in order to design Pb-free Sn-9Zn fuse elements used in electric power line. The temperature distributions in fuses were obtained on the basis of the amount of Joule’s heat generation and heat transfer depending on the ratio of the length and diameter of fuse elements. Main requirements for AC-low voltage fuses were satisfied on the promising fuse element with the size designed on the basis of the heat generation and transfer calculations. The promising size was the diameter of 2.5 mm and length of 10 mm in the smaller diameter part of two step cylindrical fuse elements. In contrast, the electrical potential and temperature distributions can be also estimated by this calculation method, regardless of a kind and shape of the fuse elements, connectors and electric wires.

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Most processes for recovering zinc from electric arc furnace (EAF) dust employ carbon as a reducing agent for zinc oxide in the dust. In the present work, the reduction reaction of zinc oxide with carbon in the presence of various additives was kinetically studied. The effects of temperature and the additives of Fe₂O₃, mill scale, and CaCO₃ on the kinetics of the reduction reaction were measured in the temperature range of 1173–1373 K under nitrogen atmosphere. The mill scale is one of byproducts generated from the steel rolling process. It was found from the experimental results that all three additives enhance the reaction rate of zinc oxide with carbon, but the effect of CaCO₃ addition is the highest. The increase in the reaction rate is because Fe₂O₃, mill scale, and CaCO₃ in the reduction reaction promote the carbon gasification reaction. The spherical shrinking core model for a surface chemical reaction control was also found to be useful in describing the kinetics of the reaction, which had an activation energy of 224 kJ/mol (53 kcal/mol) for ZnO-C reaction system, 175 kJ/mol (42 kcal/mol) for ZnO-Fe₂O₃-C reaction system, 184 kJ/mol (44 kcal/mol) for ZnO-mill scale-C reaction system, and 161 kJ/mol (39 kcal/mol) for ZnO-CaCO₃-C reaction system.

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A DSC scan of a Cu-33.5Zn-4Sn (mass%) alloy shows two exothermic peaks at around 250 and 300°C. The first peak is associated with the precipitation of α₁-plates with M9R structure, and the second peak is associated with the formation of γ precipitates. For the first peak, the α₁-plates start to nucleate at grain boundaries and grow dendritically upon heating. The primary and secondary arms of the dendritic α₁-plates grow in two preferred directions, namely, [110]_B2 and [100]_B2 of the β′ matrix. However, the stacking faults in the two arms are parallel and differ from those with the structure of the twin-accommodating variants. As the thickness and number of α₁-plates increase, the hardness of the alloy increases significantly; however, the recovery strain reduces dramatically. Additionally, the γ precipitates nucleate heterogeneously at the interface between the α₁-plate and the β′ matrix on heating above 300°C. The volume fraction of the γ precipitates increases with temperature, resulting in a reduction in the ductility of the alloy and a complete loss of its shape memory effect.

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The effect of post-annealing treatment on the texture evolution of an Al/Cu bimetal sheet as well as on the earing behavior was investigated. The earing behavior was tracked by means of measuring plastic anisotropy and deep drawing. The analysis texture evolution for as-rolled and annealed samples was performed by X-ray diffraction. The study results show that Δr⁄\\barr value increases and becomes positive when annealing temperature rises up to 300°C, in the meanwhile, a transition was observed from 45 to 0/90° earings. The mismatch in texture evolution between Al-side and Cu-side specimens was investigated. The typical recrystallization texture of Cu-side specimens mainly consists of a cube-orientation with its twins (CT) and cube texture develops at anneal temperature higher than 200°C. However, cube texture becomes the main component in Al-side specimen annealed at the temperature higher than 300°C. The mismatch in texture evolution between aluminum and copper has profound effect on the earing behavior of Al/Cu bimetal sheet. The analysis results of texture and plastic anisotropy were inductively reasoned to construct a prediction model of a Al/Cu bimetal material on earing. The earing behavior of Al/Cu bimetal material is depicted as a compromised result of the growth and decline in some certain texture components, which is agreement with the experimental findings obtained in this study.

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The purpose of this study was to evaluate the fatigue property of Ti-5Al-13Ta alloy castings for dental application since dental prostheses are used under repetitive stress condition. Dumbbell-shaped cast specimens were prepared with a centrifugal casting machine and a magnesia-based mold material. Fatigue test was performed at 310 K in 0.9% NaCl solution under repetitive loading condition with the maximum cycles at 10⁷. As a result, fatigue limit of Ti-5Al-13Ta alloy castings in NaCl solution was about 220 MPa, which was higher than those of CP-Ti, Ti-6Al-4V and Ti-6Al-7Nb alloys, previously reported. Clear striation was observed at the crack propagation area on the fracture surface. The ratio of fatigue limit to UTS was suggested to be 30% for Ti-5Al-13Ta alloy castings; this value was higher than those for Ti-6Al-4V and Ti-6Al-7Nb alloys. It was concluded that Ti-5Al-13Ta alloy castings showed good fatigue property in 0.9% NaCl solution as an α+β high-strength titanium alloy for dental prostheses.

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