冷却速度对Mg-Gd-Y-Zr合金组织和固溶行为的影响  

Influence of Cooling Rate on Microstructure and Solution Behavior of Mg-Gd-Y-Zr Alloy

作　　者：王其龙[1,2] 吴国华[1,2] 侯正全[3] 陈斌[3] 郑韫[1,2] 丁文江[1,2] 

机构地区：[1]上海交通大学轻合金精密成型国家工程研究中心,上海200030 [2]上海交通大学金属基复合材料国家重点实验室,上海200030 [3]上海航天精密机械研究所,上海201600

出　　处：《中国稀土学报》2009年第4期539-545,共7页Journal of the Chinese Society of Rare Earths

基　　金：国家973计划资助项目(2007CB613701);上海市优秀学科带头人计划(08XD14020);国家十一五科技支撑计划资助项目(2006BAE04B07-2)

摘　　要：通过金相显微镜、扫描电镜、X射线衍射、差热(DTA)分析等手段,研究了砂型差压铸造和金属型Mg-10Gd-3Y-Zr合金的组织和固溶行为差异。结果表明,与金属型相比,砂铸Mg-10Gd-3Y-Zr合金的晶粒明显粗大,而第二相含量则相对较少;冷却速度不仅影响了合金的铸态组织,同时也影响了合金随后的固溶行为。金属型条件下,500℃×8h的热处理已使第二相达到完全固溶,而砂型铸造合金则需525℃×8h的高温固溶才能使第二相溶解完全。The difference of microstructure and solution behavior of Mg-10Gd-3Y-Zr between counterpressure cast in sand mold and metal moulding were investigated by optical and scanning electron microscopy, X-ray diffraction and different thermal analysis. The results showed that the grain size of alloy cast in sand mould was much bigger than that in the metalmould, and the amount of second phase, however, was relatively less. The cooling rate affected both the microstructure and solution behavior later. In case of sand moulding, the Mg24 （Gd, Y）s was completely dissolved after 500℃ × 8 h heat treatment, whereas it needed 525 ℃× 8h to reach absolute dissolving under metal moulding.

关 键 词：差热分析 固溶行为 Mg-10Gd-3Y—Zr合金 稀土 

分 类 号：TG146.2[一般工业技术—材料科学与工程]