(1.西安工業(yè)學院42號信箱，西安710032；
2.西北工業(yè)大學，西安710072)
摘 要: 利用超高梯度快速定向凝固裝置，對DZ22合金在快速定向凝固下的枝晶組織和顯微偏析進行了研究。實驗結(jié)果表明：快速定向凝固的一次枝晶間距和二次枝晶間距及冷卻速率隨凝固速率變化有一極值。在凝固速率815μm／s時，枝晶間距(λ1，λ2)為最小，而冷卻速率為最大。各元素顯微偏析程度隨冷卻速率增大而減小。除Hf元素外，在最大冷卻速率，54℃／s(R=815μm／s)時，其余元素的偏析比均趨于1。
關(guān)鍵字: 高溫合金 定向凝固 顯微偏析
UNDER UNIDIRECTIONAL SOLIDIFICATION WITH HIGH
TEMPERATURE GRADIENT AND RAPID GROWTH RATE
（1.Box 42,Xi′an Institute of Technology,Xi′an 710032
2．Northwest Polytechnic University,Xi′an 710072）
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.
Key words: superalloy unidirectional solidification microsegregation
