顯微組織和類超塑性行為
(1.中國科學(xué)院 金屬研究所， 沈陽 110016；
2.遼寧工學(xué)院 材料與化工工程系， 錦州 121001)
摘 要: 研究了定向凝固N(yùn)i-20Al27Fe-3Nb金屬間化合物的顯微組織和高溫拉伸條件下的變形行為。結(jié)果表明，該合金的顯微組織由枝晶β-NiAl相和枝晶間γ/γ′相組成。在950～1100℃之間以5.2×10-4～1.04×10-2s-1的初始應(yīng)變速率拉伸變形時(shí)，該合金表現(xiàn)出類似超塑性的變形行為，應(yīng)變速率敏感指數(shù)m在0.21～0.45之間。在1050℃以5.2×10-3s-1的初始應(yīng)變速率拉伸時(shí)，獲得最大延伸率260%，m=0.29。通過顯微組織觀察，對這種具有類似超塑性變形行為的機(jī)理進(jìn)行了初步的討論。
關(guān)鍵字: 定向凝固；金屬間化合物；顯微組織；類超塑性
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
