稀土铝合金的枝晶间距

研究了加稀土Ｌａ、Ｃｅ或Ｙ的工业纯铝及Ａｌ－Ｍｎ,Ａｌ－Ｍｇ,Ａｌ－Ｃｕ,Ａｌ－Ｌｉ,Ａｌ－Ｃｕ－Ｌｉ,Ａｌ－Ｍｇ－Ｓｉ,Ａｌ－Ｃｕ－Ｍｇ,Ａｌ－Ｚｎ－Ｍｇ等１４种合金的枝晶间距。讨论了微量稀土、原合金元素、冷却速度和有效晶粒细化剂对枝晶的细化作用。结果表明,在各种冷速条件下,微量Ｌａ、Ｃｅ或Ｙ能显著细化工业纯铝和各种铝合金的枝晶;提出的溶质传输特征参数Ｐ０可正确反映稀土对铝合金枝晶的细化能力与原有合金元素的种类和含量的关系;冷却速度越大,稀土。对铝合金枝晶的细化作用越小;有效晶粒细化剂对铝合金枝晶的细化作用远不能与其对铝合金铸态晶粒的有效细化相提并论。

Dendrite Arm Spacings in Aluminium Alloys with Rare Earth Additions

Dendrite arm spacings of alum inium and Al-Mn, Al-Cu, Al-Li,etc.14 aluminium alloys with minor Rare Elements added have been studied. Present investigation indicates that minor addition of Rare Earth Elements La,Ce or Yobviously refined the dendrite structure of commercial pure aluminium and aluminium alloys.The refining effect of Rare Earth Elements on dendrite arm spacings was directly related to the"quality"and'quantity'of alloying elements in the base alloy,this was reflected by the solute transportation characteristic parameter Po proposed in this paper;The refining effect of Rare Earth Elements on dendrite arm spacings was also related to the cooling rate during solidification. The higher the cooling rate,the weaker the refining effect of Rare Earth Element on dendrite arm spacings.Although some additives were indicated to be very effective in refining grain size of aluminium alloys,their refining effect on dendrite arm spacings were found to be very weak.