Papers by Author: Xiao Mei Liu

Abstract: Alumina/Al-Si alloy composites were manufactured by squeeze casting. The morphology of eutectic Si in the composite was observed on scanning electronic microscope, and the modified mechanism of the eutectic Si in the composite was approached. The alumina fiber in the composite could trigger twin during the growth of Al-Si eutectic and lead to modification of the eutectic Si near the fiber.

Abstract: The effects of electromagnetic stirring on the morphology evolution of primary phase in semisolid A356 alloy slurry prepared by low superheat pouring and slightly electromagnetic stirring (LSPSES) were studied. The results indicated that the slurry containing globular-like primary phase was prepared by LSPSES, and the electromagnetic stirring within range of stirring power studied had the obvious effect on the morphology of primary phase in the slurry. The morphology of primary phase with finer size slurry was evoluted to globullar-like with increase of stirring power.

Abstract: The evolution of microstructural morphology in semisolid A356 alloy was researched under the mechanical stirring. The results showed that there was the effect of the stirring time on the microstructural morphology of semisolid A356 alloy, in which the microstructural morphology became better with the stirring time prolonging. There was also the effect of the stirring process on the microstructural morphology, in which the microstructural morphology obtained from the melt cooling to the reset solid volume fraction to start stirring was coarser than that obtained from the stirring above the liquidus temperature, but the microstructural morphology rapidly changes under the shearing force.

Abstract: Semisolid A356 alloy, which is grain-refined by Pr, was prepared by low superheat pouring. The effects of grain-refined by Pr on the morphology and the grain size of the primary α-Al in semisolid A356 alloy are researched. The results indicate that semisolid A356 alloy with particle-like and rosette-like primary α-Al can be prepared by low superheat pouring from liquid A356 alloy grain-refined by Pr. The grain size and particle morphology of primary α-Al in A356 alloy are markedly improved by 0.3wt% Pr. The refining mechanism of Pr on the morphology and the grain size of the primary α-Al in semisolid A356 alloy were delved.

Abstract: The semisolid A356 alloy slurry, which was grain-refined by Y₂O₃, was manufactured by low superheat pouring. The effects of grain-refine on the morphology and the grain size of the primary phase in semisolid A356 alloy were researched. The results indicated that semisolid A356 alloy contained Y₂O₃ with particle-like and rosette-like primary phases could be prepared by low superheat pouring. The grain size and particle morphology of primary phase in semisolid A356 alloy were markedly improved by Y₂O₃. The refining mechanism of Y₂O₃ on the morphology and the grain size of the primary α phase in semisolid A356 alloy was delved.

Abstract: Al₂O₃·SiO_2f/A356 composites contained La were fabricated by squeeze casting, and effect of La on the solute segregation and microstructure were researched. The results indicate that the microstructure in the composite can be refined by La, which enriches near the interface to be favorable to improve the wettability between the fiber and Al alloy. The phases RE-richening do not formed at the interface. There is no special influence of La on the Mg segregation in the matrix alloy. The distribution of Mg and La in the composite are near the interface.