Cu含量对Ni55Fe18Ga27合金结构和磁性的影响
Influences of Cu content on the structure and magnetism of Ni55Fe18Ga27 alloy

系统研究了Cu分别替代Fe和Ni对Ni55Fe18Ga27结构和磁性的影响．结果表明：熔炼Ni55Fe18-xCuxGa27 (x=1, 2, 3, 4)虽仍为奥氏体相结构，但伴有γ相出现；居里温度随Cu含量增加而降低，这是由于Cu掺杂引起过渡金属近邻原子间相互交换作用减弱所致；交流磁化率随Cu含量增加而降低，原因在于Fe是磁性的主要贡献者，Cu替代 Fe会削弱Fe的磁矩，从而导致合金磁性降低．熔炼、退火和甩带Ni51Cu4Fe18Ga27均存在马氏体相变．熔炼样品马氏体相变温度最高，退火和甩带样品基本相同．这一特点表明热处理方式能够改变原子排列的有序度，因此可以通过改变热处理方式来调控马氏体相变温度．
The structure and magnetism of Cu-doped in Ni55Fe18Ga27 alloy have been systematically studied in this paper. Arc-melting Ni55Fe18-xCuxGa27 (x=1, 2, 3, 4) alloys keep austenitic structure with γ phase appearing. Curie temperature decreases with increasing Cu content due to that Cu-doping reduces the exchange interaction among neighboring atoms in the transition metals. Substitution of Fe by Cu weakens the magnetic moment of Fe, which plays a primary contribution to the magnetism of Ni-Fe-Ga alloy, thus AC susceptibility decreases with increasing Cu content. Ni51Cu4Fe18Ga27 alloys prepared by arc-melting, annealing and melt-spinning (ribbon) techniques appear the martensitic transformation. The martensitic transformation temperature of arc-melting sample is higher than those of identical annealing and melt-spinning samples. This demonstrates that heat treatment method can change the order of atomic arrangement. Therefore, the martensitic transformation temperature can be dominated by changing heat treatment method.