高温度梯度定向凝固振荡性微观结构的特征和形成机制

FEATURE AND FORMATION MECHANISM OF DS OSCILLATION SUBMICROSTRUCTURE WITH HIGHER SOLIDIFIED INTERFACE TEMPERATURE GRADIENT

利用新型高温梯度（ＧＬ＝２５６～１３００Ｋ／ｃｍ）定向凝固装置，研究了籽晶法制备含细亚结构的镍基高温合金ＤＤ３单晶及二元模型合金Ａｌ０．８５％Ｃｕ晶体生长过程的组织演化与选择特征中的非稳态组织特性，特别是定向胞状振荡性微观结构的组织特征及其与定向凝固工艺条件的关系，并将其与在晶体生长透明有机物模拟装置Ｊａｃｋｓｏｎ温度平台（ＧＬ可达１５０Ｋ／ｃｍ）上原位观察到的ＣＢｒ４定向生长结果相对比，从而分析其形成机制，探索有效控制和利用该现象的工艺途径。

Non steady state microstructure selection and evolution in crystal growth of Ni base DD3 single crystal superalloy and Al 0.85%Cu, with ‘seeding’ technique and new directional solidification(DS) technique and equipment( G L=256～1 300 K/cm), was investigated comparing with that of organic simulation material of CBr4 with special Jackson type temperature platue. Feature and relationship with process condition oscillation celluar sub microstructure in different materials at different cooling rates were experimentally observed and analysed.