超高温度梯度场中的Al－Bi偏晶共生行为  

IN-SITU Al-Bi MONETECTIC COMPOSITE GROWTH UNDER ULTRA-HIGH TEMPERATURE GRADIENT

作　　者：蔡英文[1] 李建国[1] 毛协民[1] 傅恒志[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室

出　　处：《材料研究学报》1995年第3期208-212,共5页Chinese Journal of Materials Research

基　　金：国家自然科学基金

摘　　要：应用高频区熔和液态金属冷却方法，考察了定向凝固速率和温度梯度对Ａｌ－Ｂｉ偏晶共生结构的影响．发现在陡的温度梯度下，仅有很低的生长速度方能形成共生；界面前沿的液相流动破坏了共生藉以维持的稳定的三相交角，从而产生厂共生结构的异常用化与破断，利用原子扩散时间与熔体重构时间的等量关系，推导出规则型偏晶共生的动力学方程．he influence of interfacial speed and temperature gradient on directional growth of Al-Bi in-situ composites was studies by zone melting and liuqid metal cooling technique. It is found that only at very slow growth rate can a composite structure be formed when the temperature gradient is steep: and that the stirring effeCt ahead of the monotectic reaction front distorts the stable triple phase coniunction which is necessary to guarantee continuous rods / fibers. hence creates unusual coarsening and discontinuous aligned rods. From the equality or atomic diffusing time to the melt reconstructing one. an equation for regular growth of monotectic composites was derived kinetically.

关 键 词：偏晶共生 定向凝固 超高温度梯度 偏晶合金 

分 类 号：TG139[一般工业技术—材料科学与工程]