Mg_(30)Zn_(60)Y_(10)合金中二十面体准晶相的生长及形态演化  

Growth and Morphology Evolution of Icosahedral Quasicrystal Phase in Mg_(30)Zn_(60)Y_(10) Alloy

作　　者：程素玲[1] 杨根仓[1] 王锦程[1] 朱满[1] 刘峰[1] 周尧和[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《铸造》2009年第4期333-337,共5页Foundry

基　　金：国家自然科学基金(50571081);航空科学基金(04G53024)

摘　　要：利用楔形铜模具激冷浇注方法和SEM、XRD、DTA、TEM等分析手段,研究了Mg30Zn60Y10合金中二十面体准晶相(I-相)的形成过程和不同冷速下该合金的凝固组织。研究结果表明,在中等冷速下,I-相主要以初生相与剩余液相发生包晶反应形成。随着冷速的增大,I-相的生长形貌将由棱面状向枝晶状转变。当冷速大到一定程度时发生初生相的相选择。在利用DTA分析I-相的形成温度时发现,包晶反应即I-相开始形成的温度受分析时采用的温度变化速率影响。The formation process of the icosahedral quasicrystal phase （I-phase） in Mg30Zn60Y10 alloy and the different solidification microstructure formed under the different cooling rate have been investigated by using of the gravity chill-casting technique and SEM, XRD, DTA and TEM analysis. The results indicate that under a moderate cooling rate, the I-phase is formed by the peritectic reaction between a primary crystal phase and residual Mg-enriched melt. A transition from polygonal morphology to fine dendritic structure of the I-phase and primary phase selection will occur when a critical cooling rate is achieved. The peritectic reaction temperature, i.e., the formation temperature of the I-phase can be influenced by the cooling rate when DTA analysis is performed.

关 键 词：Mg—Zn-Y合金 二十面体准晶 包晶反应 相选择 

分 类 号：TG146.22[一般工业技术—材料科学与工程]