快速生长枝-胞转变过程的界面结构和微观组织SCIEI

本文利用新研制的ZMLMC定向凝固装置,研究了Ni-5wt-％Cu合金快速定向凝固条件下由树枝状生长转变为胞状生长及其过渡过程的凝固界面结构和微观组织。实验结果表明:在枝-胞转变点附近,随生长速率的增大,侧向分枝由发达逐渐萎缩,最终消失;同时一次枝晶间距减小,发生枝-胞转变时,糊状区长度急骤缩短。快速生长胞状界面与慢速生长胞状界面形态相似,但前者胞间距更小,且胞壁不光滑。

INTERFACE MORPHOLOGIES AND MICROSTRUCTURES DURING DENDRITE-TO-CELL TRANSITION AT HIGH GROWTH RATE

The interface morphologies and microstructures of the directionally solidifiedNi-5wt-%Cu alloy during the dendrite-to-cell transition at high growth rate have been investi-gated by a newly developed equipment for directional solidification. The results show in thevicinity of dendrite-to-cell transition, the well developed sidebranches become shrivelled withthe increase of growth rate and disappear at the dendrite-to-cell transition, and at the sametime the primary spacing decreases. Moreover, the length of mushy zone decreases greatlyduring the dendrite-to-cell transition. Cells obtained at high growth rate have much in commonwith those at low growth rate, but with much smaller cell spacing.