NiAl(Fe)合金组织和拉伸性能的研究

Microstructure and Tensile Properties of Intermetallic Compound NiAl(Fe) Alloys

采用光学显微镜、扫描电镜（ＳＥＭ）、透射电镜（ＴＥＭ）、电子探针（ＥＰＭＡ）、Ｘ射线（ＸＲＤ）和选区电子衍射分析（ＳＡＥＤ）研究了ＮｉＡｌ（Ｆｅ）合金的显微组织及拉伸性能。结果表明，铸态ＮｉＡｌ（Ｆｅ）合金经均匀化退火后的组织由β及β＋γ′相能阻止裂纹扩展，有利于改善合金的室温塑性。比较发现，Ｎｉ５０Ａｌ２０Ｆｅ３０合金具有最佳的室温塑性，其拉伸断由β相的解理断口和β及β＋γ′相的韧窝型断口组成。

The microstructure and tensile properties of the NiAl(Fe) alloys have been studied by means of the optical microscopy, SEM, TEM, EPMA, XRD and SAED. Results show that the as-cast Ni 50 Al 20 Fe 30 alloy annealed consists of the β phase and the β+γ′ phases, where the β+γ′ phase are in the form of network structure in most cases. The β+γ′ phase are ductile and can obstruct the cleavage crack propagation of the βphase, which assures that the Ni 50 Al 20 Fe 30 alloy exhibits the optimal ambient tesile elongation in the NiAl(Fe) alloys studied. The fractography of the Ni 50 Al 20 Fe 30 alloy consists of the cleavage fracture in the β phase and the ductiole fracture with many dimples in the β+γ′ phases.