A356合金近液相线法铸造坯料及重熔加热组织研究

采用近液相线半连续铸造法制备了A356铝合金半固态坯料,并利用电阻炉加热,采用电子显微镜研究了近液相线铸造A356铝合金在二次加热过程中的组织演变.结果表明:A356铝合金半固态坯料组织呈均匀、细小的蔷薇状分布;在585℃加热,保温10~15 min,可获得半固态加工所需的触变性组织.而且,保温温度和保温时间共同影响着二次加热组织的演变过程.随着加热温度的升高,α相的生长和球化的速度变快,保温时间越长,晶粒球化度越高.

Research on Billet and Reheat Microstructure of A356 Alloy by Nearby Liquidus Casting

Aluminum alloy A356 with uniform,fine and rose flowered grains was obtained by nearby liquidus semi-continuous casting method.The structure evolution of aluminum alloy A356 during remelting was studied by electron microscope.The results showed that when A356 alloy was heated at 585 ℃ for 10~15 min,semi-solid thixotropic organization was obtained.The remelting temperature and the time of heat insulation affect the evolutionary process of the organization.And the growth and globe rate of α phase increase with the remelting temperature increasing,while the roundness increases with the time of heat insulation.