高梯度快速定向凝固下DZ22高温合金的显微偏析

来源期刊：中国有色金属学报1996年第2期

论文作者：顾林喻 刘忠元 史正兴

文章页码：112 - 115

关键词：高温合金 定向凝固 显微偏析

Key words：superalloy ；unidirectional solidification ； microsegregation

摘    要：利用超高梯度快速定向凝固装置，对DZ22合金在快速定向凝固下的枝晶组织和显微偏析进行了研究。实验结果表明：快速定向凝固的一次枝晶间距和二次枝晶间距及冷却速率随凝固速率变化有一极值。在凝固速率815μm／s时，枝晶间距(λ₁，λ₂)为最小，而冷却速率为最大。各元素显微偏析程度随冷却速率增大而减小。除Hf元素外，在最大冷却速率，54℃／s(R=815μm／s)时，其余元素的偏析比均趋于1。

Abstract: Using an unidirectional solidification device which offers the super-high temperature gradient and the rapid growth rate of solidification, the dendritic structures and the dendritic segregation of DZ22 superalloy were investigated under the rapid unidirectional solidification. Experimental results showed that the first dendritic arm space, the second dendritic arm space and the cooling rate all had an extreme value respectively with solidifying rate increasing under the rapid unidirectional solidification. At solidifying rate 815μm/s, two kinds of dendriticarm space were minimum but the cooling rate was maximum. The microsegregation of each element decreased with increasing cooling rate. The segregation ratios of the elements all tended to 1 at maximum cooling rate except element Hf.