Zr和Y对铸态M951镍基高温合金显微组织的影响(英文)

应用光学显微镜、扫描电镜、电子探针和X射线衍射研究Zr和Y对镍基高温合金铸态组织的影响。结果表明,随着镍基合金中Zr和Y含量的增加,合金中的γ+γ′共晶数量明显增多。同时,随着Y和Zr含量的增加,合金的初生MC碳化物形貌也发生明显变化,由针状或片状转化为以孤立的块状为主。XRD衍射测试发现,加入一定量的Zr和Y后,MC碳化物的晶格常数变大。电子探针结果表明,针状或片状碳化物主要含Nb和C,而块状的碳化物则平均含有39.2%Zr和39.6%Nb。这两种元素对铸态显微组织的影响可以归结于它们所具有的原子尺寸效应。

Roles of Zr and Y in cast microstructure of M951 nickel-based superalloy

The influence of Zr and Y on the cast microstructure of a nickel-based superalloy was investigated by optical microscopy (OM),scanning electron microscopy(SEM),electron probe micro-analysis(EPMA)and X-ray diffraction(XRD).Theγ+γ′eutectic volume in the superalloy rises notably with the increase of Zr or Y content.Meanwhile,the morphologies of primary MC carbides change from needle and platelet-like to blocky shape with increasing Zr and Y doped.The XRD results show that the primary MC carbide lattice constant increases with Zr and Y additions,and EPMA investigation shows that the platelet-like MC carbides contain primarily Nb and C,while those carbides in blocky shape have 39.2%Zr and 39.6%Nb in average,.These influences on the cast microstructure can be attributed to the atomic size effects of Zr and Y.