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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。
In this paper, the effect of hafnium content on the elemental segregation behavior, microstructure and ductility of DZ22 in the directionally solidified superalloy was investigated. The experimental results show that hafnium is a strong segregation element. The addition of hafnium to DZ22 alloy reduced segregation of elements and changed the relative contents of Ti, W, Nb and Cr in each phase. The addition of hafnium increases the volume fraction of eutectic γ / γ ’, expands the range of solidification and improves the contact of capillary shrinkage channels in the late stage of solidification, thus alleviating the tendency of hot cracking. With the increase of hafnium content, the long-term performance of the alloy at mid-temperature, especially the mid-temperature lateral durability has been improved.