The thermal conductivity of alloys is gradually becoming appreciated. It is often assumed that heat treatment can improve the thermal conductivity of Al-Si-Mg-Cu alloys, but there has been little relevant research. This paper studies the effects of different casting processes and short T6 heat treatment (ST6) on the thermal conductivity and mechanical properties of Al-Si-Mg-Cu alloys. The results show that a microstructure with fine α-Al crystal grains can be obtained by semi-solid die casting (SSDC), improving the mechanical properties of the Al-Si-Mg-Cu alloy in the as-cast state. After SSDC, the size and aspect ratio of eutectic silicon can be reduced by ST6 treatment, effectively improving the thermal conductivity and mechanical properties of the alloy. Finally, the influence of eutectic silicon on electron transport is analyzed in detail. With the SSDC + ST6 processing technology, Al-Si-Mg-Cu alloys with excellent thermal conductivity and mechanical properties can be obtained.

In this paper, the effects of size, morphology and distribution of eutectic silicon on the thermal conductivity of Al-8Si alloy modified by Sr (0.04, 0.08, 0.12 wt.%) and Sb (0.1, 0.3, 0.5 wt.%) elements with T6 heat treatment were investigated. The results show that the modified fibrous eutectic silicon has a significant capability of improvement of thermal conductivity, while the amount of the modifier has a relatively weak effect on thermal conductivity. After T6 treatment, the fracture or spheroidization of the flake eutectic silicon and the disappearance of clustering phenomenon could raise thermal conductivity, but the coarsening of fibrous eutectic silicon is inconducive to thermal conductivity. Finally, the effect of eutectic silicon on electron transport is analyzed in detail, which could provide a reference for enhancing the thermal (or electrical) conductivity of hypoeutectic Al-Si alloy through effective microstructure control.

Co-doped Zn₂SnO₄–graphene–carbon nanocomposites have been prepared for the first time through a convenient one-step hydrothermal method.

Forming magnesium alloys with rare earth elements (La, Gd, Nd, Y, Ce) is a routine method for modifying their microstructure and properties. In the present work, the effect of Ce addition on the microstructure evolution and the mechanical properties of as-extruded Mg-8Al-0.5Zn (AZ80) alloy was investigated. All of the extruded AZ80-xCe (x = 0, 0.2, 0.8 and 1.4 wt %) alloys exhibited equiaxed grains formed by fully dynamic recrystallization, and the grain size of the extruded AZ80 alloy was remarkably reduced by ~56.7% with the addition of 1.4 wt % Ce. Furthermore, the bulk-shaped Al₄Ce phase formed when Ce was first added, with the Ce content rising to 0.8 wt % or higher, and Al₄Ce particles in both the nano- and micron sizees were well distributed in the primary α-Mg matrix. The area fraction of the Al₄Ce particles expanded with increasing Ce content, providing more nuclei for dynamic recrystallization, which could contribute to the grain refinement. The results of the tensile tests in this study showed that Ce addition effectively improved the room temperature formability of the as-extruded AZ80 alloy, without sacrificing strength. The significantly improved mechanical properties were ascribed to excellent grain refinement, weakened texture strength, an increased Schmid factor, and a reduced area fraction of low-angle grain boundaries, all resulting from Ce addition to the as-extruded AZ80 alloy. The contribution of the nano-Al₄Ce precipitates on improving the mechanical properties was also discussed in this paper.