稀土La对半固态A356初生相细化机制的研究

Research of rare earth La on refining mechanism of primary α phase in semisolid A356 alloy

利用Al-La稀土中间合金对液态A356铝合金进行了细化处理,并用低过热度浇注技术制备了半固态A356铝合金浆料,研究了稀土La对所制备半固态A356铝合金的初生α相形貌和尺寸的影响.研究结果表明,含有适量稀土La的A356铝合金经低过热度浇注可制备具有颗粒状和蔷薇状初生α相的半固态浆料,稀土La可显著改善半固态A356铝合金中初生α相的晶粒尺寸和颗粒形貌.稀土La对半固态A356铝合金的初生α相细化机理可能与稀土在铝合金中诱发的共晶反应有关.

The semisolid slurry of A356 alloy,which is grain-refined by Al-La master alloy,is manufactured by low superheat pouring.The effects of La addition on the morphology and the size of the primary α phase in the semisolid A356 alloy are investigated.The results indicate that semisolid A356 alloy contained certain La addition with particle-like and rosette-like primary α phase can be prepared by low superheat pouring.The size and morphology of primary α phase in the semisolid A356 alloy are markedly improved by La addition.The refining mechanism of La of the primary α phase in semisolid A356 alloy is concerned with the eutectic reaction induced by La in the alloy.