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采用真空电弧炉熔炼方法制备了添加稀土元素Gd的Ni-33Al-28Cr-5.9Mo-0.1Hf(原子分数,%)合金,运用扫描电镜(SEM)、电子探针显微分析(EPMA)及透射电镜(TEM)分析了该合金的微观组织形貌和相组成,采用Gleeble 1500进行了室温及高温压缩性能测试.研究表明,稀土元素Gd极少部分固溶于NiAl与Cr(Mo)相中,大部分参与形成Heusler相.适量Gd可细化共晶合金的组织,即减小NiAl/Cr(Mo)共晶胞的尺寸及共晶层片的间距,因此提高了合金的室温压缩屈服强度与压缩塑性,但对1373 K时的压缩强度影响较小.当Gd含量达到0.1(质量分数,%)时,共晶胞界宽化,且胞界的Cr(Mo)相出现粗化及不规则分布现象,导致室温和高温压缩性能降低.
Ni-33Al-28Cr-5.9Mo-0.1Hf (atomic fraction,%) alloy with rare earth element Gd was prepared by a vacuum arc furnace melting method. The microstructure of the alloy was characterized by scanning electron microscopy (SEM), electron probe microanalysis The microstructure and phase composition of the alloy were analyzed by transmission electron microscopy (TEM), and the compressive properties at room temperature and high temperature were measured by Gleeble 1500. The results show that rare earth element Gd is rarely partially dissolved in NiAl and Cr (Mo) Most of them participate in the formation of Heusler phase.The appropriate amount of Gd can refine the eutectic alloy microstructure, that is to reduce the NiAl / Cr (Mo) eutectic cell size and eutectic layer spacing, thus increasing the alloy’s compressive yield strength at room temperature and Compressive plasticity, but little effect on the compressive strength at 1373 K. When the Gd content reaches 0.1 (mass fraction,%), the eutectic cell boundary broadens and the Cr (Mo) phase appears coarse and irregular Distribution phenomenon, resulting in low temperature and high temperature compression performance.