In this study, pure Al powder was compression-molded on the surface of a flame-retardant Mg alloy plate, and integration of pure Al and Mg alloy was attempted by melting and solidification in air. In order to integrate different materials by liquid diffusion of metal elements, the structure, composition phase and hardness of the formed integrated materials were investigated.

  It was found that heating the specimens for 180s results in melting and liquid diffusion between Al and Mg. When heated and melted with pure Al down and Mg alloy up (Type B), shrinkage cavity was formed on the former Mg alloy side of the former Al/former Mg alloy interface. When heated at 450s, the specimen was composed of Al-Mg system stable phases of Al₃Mg₂ and Al₁₂Mg₁₇, and Al-Mg system metastable phases of Al_0.37Mg_0.63 and Al_0.1Mg_0.9. In Type A with pure Al up and Mg alloy down and Type B, stable phases of Al₃Mg₂ and Al₁₂Mg₁₇ were formed on the former Al side. The constituent phase of the former Mg alloy side was composed of metastable phases of Al_0.37Mg_0.63 and Al_0.1Mg_0.9, but the structure morphologies of Type A and B differed near the surface of the former Mg alloy side, and the primary phase was Al_0.37Mg_0.63 and Al_0.1Mg_0.9 respectively. The final solidification phase consisted of eutectic phases of Al_0.37Mg_0.63 and Al_0.1Mg_0.9. The hardness on the former Al side was about 250HV, and the hardness on the former Mg alloy side had decreased. Type B was evaluated to be lower than Type A.

  Microstructures in as-cast state, after thermal shock and creep test of austenitic heat resistant cast steel with tungsten were investigated using scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffractometry and X-ray photoelectron spectroscopy. The results indicate that tungsten dissolves in austenitic matrix and promotes the microstructural refinement of primary carbides. In addition, crystalized tungsten carbide is also detected. Furthermore, W substitutes for Fe and Cr in the primary chromium carbides, improving thermal stabilization. As a result, primary carbides are difficult to decompose at elevated temperature. Microstructures which provide both of solid solution strengthening and dispersion strengthening are effective for enhancing high temperature properties of austenitic heat resistant cast steel.

  A356 alloy strips fabricated via high-speed twin-roll casting were cold rolled at the reductions of 0 %, 12 %, 30 %, 50 % and 73 % and then solution treated at 793 K for 1 h. Microstructure observations and tensile tests were performed for the processed strips. Upon increasing the reduction from 0 % to 50 %, an improvement in elongation with significant anisotropy was observed ; the elongation along the transverse direction was inferior to that in the rolling direction. However, on further reduction up to 73 %, this anisotropy was eliminated and an elongation above 20 % was achieved. This behavior is caused by the characteristic changes occurring in the second-phase particles that are located in the mid-thickness region of the strip. To achieve a high elongation without anisotropy, a process for refining the coarse particles in the mid-thickness region of the twin-roll-cast strips and homogeneously dispersing them into the matrix needs to be developed.