稀土元素Gd对NiAl-Cr(Mo)-Hf共晶合金的组织和压缩性能的影响

来源期刊：金属学报2010年第5期

论文作者：梁永纯 郭建亭 盛立远 周兰章

文章页码：528 - 532

关键词：NiAl基合金； 稀土Gd； 金属间化合物； 组织； 力学性能

Key words：NiAl base alloy； rare earth Gd； intermetallics； microstructure； mechanical property

摘    要：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.

Abstract: The effects of rare earth element Gd on the microstructure and compressive properties of Ni-33Al-28Cr-5.9Mo-0.1Hf(atomic fraction,%) eutectic alloy at room temperature and 1373 K were studied.Very little amount of Gd dissolved in the NiAl and Cr(Mo) phases,and much more amount of Gd distributed in Heusler phase.Addition of Gd induced the microstructural refinement, including the decrease of the eutectic cell size and the lamellae spacing between the NiAl and Cr(Mo) plates.The proper Gd addition leads to the improvement of the compressive yield strength and ductility of the alloy at room temperature,but Gd has a little effect on the compressive properties at 1373 K. However,the Cr(Mo) phase was coarsened and distributed irregularly when 0.1 Gd(mass fraction, %) was added into the alloy,which resulted in the decrease of compressive properties at the testing temperature.