Ni基单晶高温合金中固态枝晶γ＇沉淀相的演化  

EVOLUTION OF DENDRITICγ'IN A SINGLE CRYSTAL Ni-BASE SUPERALLOY

作　　者：孔丹[1] 张静华[1] 张志亚[1] 李英敖[1] 胡壮麒[1] 

机构地区：[1]中国科学院金属研究所

出　　处：《材料研究学报》1995年第6期481-485,共5页Chinese Journal of Materials Research

基　　金：国家自然科学基金

摘　　要：Ｎｉ基单晶高温合金中的固态枝晶γ＇具有以［１１１］为择优取向的八个枝轴为一体的三维形貌特征．在其它处理条件相同，唯时效时间不同的情况下，时效初期的枝晶γ＇表面随着时间的延长发生由外及里的分裂，其上γ＇的尺寸也随之由大变小，分析原因与弹性畸变能的释放有关分裂过程在１ｈ内完成时效后的枝晶γ＇表现为由众多个按一定取向排列的小方γ＇包围而成．固态枝晶γ＇按照台阶机制长大，时效初期弹性畸变能起主要作用，而后期则是浓度梯度差异的影响。The stereographic morphology of a dendrite γ'is octet of branches characterized in<111>direction. With the extension of ageing time, the surface of dendritic γ'formed during the initial stage will split into numerous small cubic γ'which array in a given order. The split can be explained by the release of elastic strain energy caused by the misfit of γ'and γ'during the growth of dendritic γ'.The growth mechanism of dendritic γ'is also proposed.The ledges which are preferentially present at the corners of a tetragenal dominate the dendrite growth. During the initial stage of ageing treatment,the formation of ledges is influenced by the combination of γ'preferential direction <111>,concentration gradient, elastic strain energy,but after the split, the former two are the main factors.

关 键 词：固态枝晶 形貌演化 台阶机制 镍基 高温合金 

分 类 号：TG132.32[一般工业技术—材料科学与工程] TG111.5[金属学及工艺—合金]