(中国科学院 金属研究所高温合金部， 沈阳 110016)
摘 要: 研究了定向凝固NiAl合金NiAl-25Cr、 NiAl-15Cr、 NiAl-27Fe-3Nb和NiAl-5Mo-0.5Hf的超塑性行为及其变形机制。 结果表明： 合金在一定的变形条件下均表现出超塑性行为，位错的滑移和攀移行为提供了主要的应变量； 超塑性变形过程中的稳态流变源于变形过程中所发生动态回复或再结晶产生的软化与应变硬化的平衡； 动态回复或再结晶过程一方面在晶粒内部削弱了位错滑动的阻力，另一方面协调了晶界之间的变形， 使合金以超塑性方式变形。
关键字: 定向凝固； NiAl合金；超塑性
directionally solidified NiAl alloys
（Superalloy Department, Institute of Metal Research,
Chinese Academy of Sciences, Shenyang 110016, China）
Abstract: The superplastic deformation behavior and mechanism of directionally solidified NiAl alloys(NiAl-25Cr, NiAl-15Cr, NiAl-27Fe-3Nb, NiAl-5Mo-0.5Hf) were investigated. The results reveal that all these alloys exhibit superplastic deformation behavior in certain conditions. Dislocation behavior(glide and climb) provides the main superplastic strain for these alloys. The steady state during superplastic deformation arises from the balance between strain hardening(dislocation behavior) and strain softening(dynamic recovery or recrystallization). Both weakening internal stress and accommodating boundaries from dynamic recovery or recrystallization process make it possible for superplastic deformation to proceed on these alloys.
Key words: directional solidification; NiAl alloys; superplasticity
