NiAl—Cr(Zr)金属间化合物合金的高温蠕变

HIGH TEMPERATURE CREEP OF NiAl-Cr(Zr) INTER-METALLIC ALLOY

研究了多相金属间化合物 ＮｉＡｌ—３３．５Ｃｒ－０．５Ｚｒ合金的显微组织和高温拉伸蠕变行为．铸态合金由β－ＮｉＡｌ和α－Ｃｒ组成共晶胞及沿共晶胞界分布的 Ｎｉ２ＡｌＺｒ（Ｈｅｕｓｌｅｒ）相组成．热等静压处理后，胞界处的 Ｎｉ２ＡｌＺｒ相转变为富 Ｚｒ相．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，不同温度、负荷下的蠕变应变几乎相同，均为４５％左右，且蠕变后的显微组织变化不大，蠕变变形机制为位错滑移和攀移控制下的动态回复与动态再结晶，不是单独由扩散所控制．蠕变断裂数据符合Ｍｏｎｋｍａｎ—Ｇｒａｎｔ关系．

The microstructure and high temperature tensile creep behavior of multiphase NiAl-33.5Cr-0.5Zr intermetallic alloy have been investigated. The as-cast alloy consists of,beta -NiAl, alpha -Cr and Ni2AlZr (Heusler) phase. After hot isostatic press (HIP) at 1573 K, 100 MPa for 2 h, the Ni2AlZr phase converted into Zr-rich phase. 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 are nearly same, about 45%, and the microstructure of the post-creep deformation is nearly the same as that of pre-creep deformation. The creep deformation mechanism is the dynamic recovery and the dynamic recrystallization that are controlled by dislocation slide and dislocation climb, but not the diffusion. The creep fracture data follow the Monkman-Grant relationship.