抽拉速率对定向凝固Ti-47Al-2Cr-2Nb-0.8B合金组织的影响

来源期刊：金属学报2010年第7期

论文作者：杨莉莉 郑立静 肖志霞 闫洁 张虎

文章页码：879 - 884

关键词：TiAl基合金； 凝固组织； 细化效果； 硼化物； 凝固速率

Key words：TiAl based alloy； solidification microstructure； grain refinement； boride； solidification rate

摘    要：研究了4种抽拉速率(0.36,5,10和20 mm/min)获得的定向凝固Ti-47Al-2Cr-2Nb-0.8B合金的凝固组织、硼化物形态以及B对合金晶粒的细化作用.结果表明,抽拉速率影响了合金凝固的初生相、硼化物种类和硼化物析出的顺序,从而形成了不同的凝固路径.在不同的凝固路径下,合金的晶粒细化效果和硼化物的形态均不同.当抽拉速率为5 mm/min时,合金的凝固路径最有利于合金的晶粒细化,并且硼化物尺寸最小.

Abstract: The microstructures,morphology of boride and grain refinement in directional solidified Ti-47Al-2Cr-2Nb-0.8B alloy with different withdrawal rates have been investigated.The results indicated that the primary phase,borides and their precipitation consequence varied with the increasing of withdrawal rates (0.36,5,10 and 20 mm/min).The morphologies of borides and grain refinement were affected by the solidification paths due to the different withdrawal rates.The alloy with fine grains and borides were obtained at the withdrawal rate of 5 mm/min.