Co41Ni33Al26合金的再结晶、马氏体相变和铁磁特性

Recrystallization,Martensite Transformation and Magnetic Characteristic of Co41Ni33Al26 Alloy

研究了Co41N i33A l26铁磁性形状记忆合金的再结晶行为和组织变化规律,采用振动磁力计(VSM)和示差热分析仪(DSC)分析了合金磁性和马氏体相变特点。结果表明,经43.65%的大压下量冷轧变形的Co41N i33A l26合金在低于1000℃发生再结晶,随着淬火温度的升高,合金中β相体积分数不断增加。冷轧组织中在β/γ相界面上有很多微裂纹,这是由于两相变形不协调而形成的,微裂纹的形成有利于合金的塑性变形,在高于1200℃处理时微裂纹消失,表现出“自愈合”能力。该合金的马氏体相变温度和居里点都随着淬火温度的升高而升高,居里点始终高于马氏体相变温度,且马氏体相的磁晶各向异性高于β母相的,说明该合金是很好的铁磁性形状记忆合金的候选材料。

Recrystallization behavior and microstructure of cold rolling Co41Ni33Al26 alloy were investigated by optical observation and hardness tester. Magnetic properties and martensite transformation were studied by vibrating sample magnetometer（ VSM ）and differential scanning calorimetry （DSC）respectively. The results show that the cold rolling Co41Ni33Al26 alloy with a high compress reduction about 43.65% reerystallizes below 1000℃. The volume fraction of β phase increases with the increase of quenching temperature. Many micro-cracks exist at the interface of β/γ phases in cold rolling mierostrueture due to the disaeeorded deforming of β/γ two phases and their existing are benefited to plastic deformation. Furthermore those cracks disappeared when quenching above 1200℃ ,it means that this alloy have a self repairing ability. Both the values of martensite transformation temperature and Curie point are elevated with the increase of quenching temperature and Curie points are always higher than the martensite transformation temperatures at different quenching temperatures, moreover, magnetocrystalline anisotropy of martensitic phase is higher than that of β mother phase ,these results suggest that Co41Ni33Al26 alloy is a promising ferromagnetic shape memory alloy.