摘要
采用液态金属冷却法,对一种含4wt.%Re的单晶高温合金进行高温度梯度定向凝固试验,并通过改变固溶处理温度和时间对其进行多步固溶处理。结果表明:高温度梯度定向凝固可以显著地细化枝晶,降低Re、W、Ta等难熔元素的枝晶偏析;溶质的特征扩散距离也随枝晶的细化而减小,经多步固溶处理后,合金各组元的残余偏析程度显著降低;此外,适当提高固溶热处理温度,可以起到减轻枝晶偏析的作用。
A Ni-base single-crystal superalloy containing 4wt.%Re was directionally solidified under liquid metal cooling （LMC）, followed by stepwise solution treatments. Under high thermal gradient, the dendrite structures are greatly refined with increasing withdrawal rates. After the stepwise solution heat treatments, the residual segregation of alloying elements such as Ta, Re and W etc., reduces with the refined structure, which can be attributed to the reduced characteristic diffusion distance. In addition, as the increase of solution-treated temperatures, the residual segregation of refractory elements can be reduced.
出处
《铸造》
CAS
CSCD
北大核心
2012年第1期84-88,共5页
Foundry
基金
国家自然科学基金项目(50931004
50827102)
国家重点基础研究发展项目(2010CB631202
2011CB610406)
关键词
镍基单晶高温合金
定向凝固
微观偏析
固溶热处理
Ni-base single-crystal superalloys
directional solidification
microsegregation
solution treatment
