ժҪ As a potential ferromagnetic shape memory alloy, Ni-Co-Al has excellent mechanical properties, large magentic-field-induced strain and high martensitic transformation temperature. The relationship between microstructure and performance (mechanical and magnetic properties) of Ni-Co-Al with different Co/Al atomic ratios (RCo/Al) was investigated. Samples exhibit �� and �� dual-phase structure. The �� phase grows coarse and the volume fraction of �� phase increases with the rise of RCo/Al. Besides, sample with high amount of �� phase content has smaller �� grains owing to the pinning effect of �� phase. The martensite, transformed from �� phase, is tetragonal L10 structure with a (111) twinning plane. The martensitic transformation temperature of samples ascends with increasing RCo/Al owing to more Co embedded into the cell, which makes the valence electron concentration (e/a) of system rise. The saturation magnetization (Ms) of samples increases as RCo/Al rises because Co-rich �� phase has excellent magnetic property. Meanwhile, both compressive and micro-hardness tests reveal that the samples containing more �� phase have excellent ductility due to the intrinsic good ductility nature of �� phase.
Abstract��As a potential ferromagnetic shape memory alloy, Ni-Co-Al has excellent mechanical properties, large magentic-field-induced strain and high martensitic transformation temperature. The relationship between microstructure and performance (mechanical and magnetic properties) of Ni-Co-Al with different Co/Al atomic ratios (RCo/Al) was investigated. Samples exhibit �� and �� dual-phase structure. The �� phase grows coarse and the volume fraction of �� phase increases with the rise of RCo/Al. Besides, sample with high amount of �� phase content has smaller �� grains owing to the pinning effect of �� phase. The martensite, transformed from �� phase, is tetragonal L10 structure with a (111) twinning plane. The martensitic transformation temperature of samples ascends with increasing RCo/Al owing to more Co embedded into the cell, which makes the valence electron concentration (e/a) of system rise. The saturation magnetization (Ms) of samples increases as RCo/Al rises because Co-rich �� phase has excellent magnetic property. Meanwhile, both compressive and micro-hardness tests reveal that the samples containing more �� phase have excellent ductility due to the intrinsic good ductility nature of �� phase.
Jia JU,Feng XUE,Liu-xia SUN. Structure and Performance Changes of Ni-Co-Al Shape Memory Alloys in Relation to Co/Al Atomic Ratio[J]. �й������ڿ���, 2015, 22(7): 652-656.
Jia JU,Feng XUE,Liu-xia SUN. Structure and Performance Changes of Ni-Co-Al Shape Memory Alloys in Relation to Co/Al Atomic Ratio. Chinese Journal of Iron and Steel, 2015, 22(7): 652-656.
2015, Vol. 22 
