显微组织和类超塑性行为
(1.中国科学院 金属研究所， 沈阳 110016；
2.辽宁工学院 材料与化工工程系， 锦州 121001)
摘 要: 研究了定向凝固Ni-20Al27Fe-3Nb金属间化合物的显微组织和高温拉伸条件下的变形行为。结果表明，该合金的显微组织由枝晶β-NiAl相和枝晶间γ/γ′相组成。在950～1100℃之间以5.2×10-4～1.04×10-2s-1的初始应变速率拉伸变形时，该合金表现出类似超塑性的变形行为，应变速率敏感指数m在0.21～0.45之间。在1050℃以5.2×10-3s-1的初始应变速率拉伸时，获得最大延伸率260%，m=0.29。通过显微组织观察，对这种具有类似超塑性变形行为的机理进行了初步的讨论。
关键字: 定向凝固；金属间化合物；显微组织；类超塑性
deformation behavior of directionally
solidified NiAl-Fe-Nb intermetallic alloy
（1.Institute of Metal Research, Chinese Academy of Sciences,
Shenyang 110016, China;
2.Department of Materials and Chemical Engineering,
Liaoning Institute of Technology, Jinzhou 121001, China）
Abstract:The microstructure and deformation behavior in high temperature tension of a directionally solidified (DS) Ni-20Al-27Fe-3Nb intermetallic alloy have been investigated. The results show that the microstructure consists of dendriti c β-NiAl phase and interdendritic γ/γ′ phase. This alloy exhibits superplastic-like behavior deformed at 950～1100℃ with initial strain rate range of 5.2×10-4～1.04×10-2s-1 and the strain rate sensitivity index m=0.21～0.45. The maximum elongation of 260% with m=0.29 was obtained at 1050℃ and an initial strain rate of 5.2×10-3s-1. The mechanism for the superplastic-like deformation behavior has also been discussed by the observation of the microstructures.
Key words: directional solidification; intermetallic compound; microstructure; superplastic-like deformation
