Superplasticity of Directionally Solidified NiAl-15Cr Alloy at High Temperature

作     者：ZHANG Guang-ye ZHANG Hua ZHANG Hou-an WU Xian-ming GUO Jian-ting 

作者机构：School of Electromechanism Engineering Hunan University of Science and Technology Xiangtan 411201 HunanChina Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 Liaoning China 

出 版 物：《Journal of Iron and Steel Research International》 (国际钢铁研究杂志)

年 卷 期：2006年第13卷第4期

页      面：44-48页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：ItemSponsoredbyNationalNaturalScienceFoundationofChina(59895152)andNationalAdvancedMaterialsCommitteeofChina(8637150050030) 

主　　题：intermetallics directional solidification superplasticity microstructure 

摘      要：Ni-25Al-15Cr （atomic percent, %） alloy was directionally solidified （DS） under argon atmosphere in an Al2O3-SiO2 ceramic mold by standard Bridgman method. The microstructure of the as-fabricated alloy was studied using optical microscope, X-ray diffractometer, and scanning electron microscope. The alloy consisting of dendritic β- NiAl phase, interdendritic γ/γ′ phase, and transient layer γ′ phase, has been investigated. This alloy exhibits superplastic deformation behavior at 1 273-1 373 K over an initial strain rate range of 8. 35×10 ^-4 -1. 67×10^-2s^-1. The maximum elongation of 280% with strain rate sensitivity index m= 0. 22 was obtained at the temperature of 1 323 K and an initial strain rate of 8. 35×10^-3s^-1. Transmission electron microscopy （TEM） observations indicate that the superplastic deformation stems from the balance between high resistance （by dislocation sliding） and strain softening （by dynamic recovery and recrystallization）.