摘要
本文研究了铪含量对定向凝固高温合金DZ22的元素偏析行为和相组织以及中温持久性能的影响。试验结果表明,铪是一个强烈的偏析元素。在DZ22合金中加入铪,使元素的偏析减少,而且改变了Ti,W,Nb,Cr在各相中的相对含量。铪的加入,增加了共晶γ/γ′的体积分数,扩大了凝固范围,改善了合金凝固后期的毛细补缩通道的联系,从而减轻了热裂倾向性。随着铪含量的提高,合金的中温持久性能,特别是中温横向持久性能有所提高。
Test results show that Hafnium is a strong segregative element. Hf-addition in alloy DZ_22 reduces the dendrite segregation of other elements and alters the relative content of alloying elements Ti, W, Nb and Cr in various phases. As Hf is added into the alloy the volume fraction of γ/γ′eutectic is increased and the temperature range between solidus and liquidus is expanded, which may maintain the effective linkage of interdendritic capillary feeding channel, thus improving the resistance of DS castings to the thermal cracking. With increasing Hf content the stress-rupture properties, in particular, the transverse stress-rupture properties of alloy DZ_22 at intermediate temperature are obviously enhanced.
出处
《航空材料学报》
EI
CAS
CSCD
1989年第2期1-7,共7页
Journal of Aeronautical Materials
