半固态A356合金重熔加热时初生相的组织演变

利用低过热度浇注技术制备了半固态A356铝合金坯料,研究了半固态温度区间重熔加热时半固态A356铝合金坯料的初生相形貌的转变过程.结果表明,在半固态两相区保温,半固态A356合金的初生相逐渐团球化,该过程随保温温度的升高而加快.半固态A356铝合金晶粒的圆度与保温温度和保温时间的关系不大,但晶粒的尺寸随着保温温度和保温时间的增加而增大.半固态A356合金试样重熔加热最佳工艺制度为583℃下保温30min,其晶粒平均等积圆直径为80μm,晶粒平均圆度为0.83.

Microstructure Evolution of Primary Phase in Semi-solid A356 Alloy during Reheating

This paper studies the transform course for primary phase morphology of the semi-solid A356 alloy billet,produced by low superheat pouring during reheating in solid-liquid phase region.The results indicate that the primary phase of semi-solid A356 alloy is gradually spheroidized during the holding in solid-liquid phase region,in which spheroidization is speeded up with the increase of the holding temperature.There is little effect of holding temperature and holding time on grain roundness of semi-solid A356 alloy,but the grain size of the alloy increases with increasing of the time and the temperature.The optimizing reheating technology of semi-solid A356 alloy is that the billit is held 30 min at 583℃,in which the average equal-area-circle grain diameter is 80μm,and the average grain roundness is 0.83.