非平衡凝固条件下Zn-5Al合金的组织形成

对Zn-5Al合金采用液淬凝固和定量金相统计试验,考察了合金在非平衡冷却凝固过程中组织的形成和转变。研究表明:合金在非平衡凝固下析出初生富铝相α,它随着冷却速度的提高是逐渐减少的;初生相逐渐从胞状向树枝状转变。Zn-5Al合金在非平衡凝固条件下因析出初生相而获得亚共晶组织,冷速较大时共晶组织皆无明显的共晶核心,并且共晶层片组织逐渐变细,有的甚至无法看到,只有在共晶团搭界处才可看出明显的层片,共晶团内部的共晶层片基本呈无序状态。通过对本试验结果探讨,定性得到了锌铝合金共晶共生区相图,为以后研究Zn-5Al合金在非平衡凝固条件下凝固结晶提供了一些参考。

Formation of Structure During Zn-5Al Alloy Nonequilibrium Solidification Process

The structure formation and transformation of Zn-5Al alloy in the nonequilibrium solidification process were investigated by the liquid-quenching solidification process and the qualitative metallography analysis. The resuults show that,in the nonequilibrium solidification process, some primary Al-rich phase separate out in the structure of Zn-5Al alloy,which become less with the increase of cooling rate, and primary phase transform from cystiform to arborous. Zn-5Al alloy attained hypoeutectic structure because of primary phase, there are not cores for all of eutectic cells, eutectic lamellar spacing become thin, some lamellar spacing is invisibility, lamellar spacing is visibility in the interphase, eutectic lamellar is out-of-order in crystal.The test results were discussed,the eutectio symbiosis phase diagram Zn-5Al alloy was obtained. It has some reference value for later study.