稀土对ZA-27合金高温性能的影响

Effect of Rare Earths on the High Temperature Properties of ZA-27 Alloys

研究了ｃＣｅ≥４５％（ｗｔ）的混合稀土对ＺＡ－２７合金显微组织及高温机械性能的影响。结果表明，在锌铝合金中，稀土元素可与Ａｌ、Ｚｎ、Ｃｕ等形成多种复杂成分化合物，其硬度高，热硬性好，分散于晶界或枝晶间，细化了组织，且有效地阻碍了高温时基体的变形和晶界移动。添加适量的稀土，可使ＺＡ－２７合金在１５０℃时的抗拉强度提高３０％，硬度提高２５％，延伸率虽有所下降，但冲击韧性却得以改善。同时发现，室温强度变化不大，唯塑性、韧性略有下降。

The effect of mixedRE of cCe≥45%(wt) on the high temperature mechanical properties and morphology of ZA-27 alloys has been investigated. The results show that rare earth elements can react with elements Al, Zn, Cu etc. to form some compounds of complex constituents which have high hardness and good hothardness and can disperse in crystalinterfaces or branch crystal interfaces so that the alloy has been refined and the deformation of matrix and movement of crystalinterfaces at high temperature are tempered. Addition of RE in appropriate contents can result in increase of tensile strength to about 30% and hardness to 25% at 150 ℃. Elongation is somewhat decreased, but impact toughness is improved. The observation shows that the strength at room temperature changes a little although the plasticity and impulsive tenacity decrease slightly.