【摘要】 研究了定向凝固NiAl-28Cr-5Mo-1Hf合金的显微组织和高温拉伸蠕变行为.该合金由NiAl相、 Cr(Mo)相和少量聚集在NiAl和Cr(Mo)相界处的Ni2AlHf(Heusler)相组成.蠕变曲线表现为较短的减速蠕变阶段和较长的稳态蠕变阶段及较高的蠕变应变,且蠕变后显微组织的变化不大.该合金的蠕变由晶格自扩散引起的位错攀移所控制.蠕变断裂数据符合Monkman-Grant关系.更多还原

【Abstract】 The microstructure and high temperature tensile creep behavior of directionally solidified NiAl-28Cr-5Mo-lHf alloy have been investigated. The alloy is composed of NiAl matrix, Cr(Mo) phase and a small amount of Ni2AlHf (Heusler) phase which discontinuously distributed at NiAl and Cr(Mo) phase boundaries. All of the creep curves under different temperatures and loadings have similar shape of a short primary creep and dominant steady creep stages, the creep strain is relatively large, and the microstructure of the post-creep deformation is nearly the same as that of pre-creep deformation. The creep deformation is controlled by dislocation climb resulting from lattice self-diffusion. The creep fracture data follow the Monkman-Grant relationship.更多还原