Microstructure and martensitic transformation behavior of Ni56-xMn25FexGa19 shape memory alloys
来源期刊：Rare Metals2014年第1期
论文作者：Yan Xin Liang Chai
文章页码：41 - 46
摘 要：Microstructure, martensitic transformation behavior, mechanical and shape memory properties of Ni56-x Mn25 Fex Ga19（x = 0, 2, 4, 6, 8） shape memory alloys were investigated using optical microscopy（OM）, X-ray diffraction analysis（XRD）, differential scanning calorimeter（DSC）, and compressive test. It is found that these alloys are composed of single non-modulated martensite phase with tetragonal structure at room temperature, which means substituting Fe for Ni in Ni56 Mn25 Ga19 alloy has no effect on phase structure. These alloys all exhibit a thermoelastic martensitic transformation between the cubic parent phase and the tetragonal martensite phase. With the increase of Fe content, the martensitic transformation peak temperature（Mp） decreases from 356 °C for x = 0 to 20 °C for x = 8, which is contributed to the depressed electron concentration and tetragonality of martensite. Fe addition remarkably reduces the transformation hysteresis of Ni–Mn–Ga alloys. Substituting Fe for Ni in Ni56 Mn25 Ga19 alloy can decrease the strength of the alloys and almost has no influence on the ductility and shape memory property.
Yan Xin1，Liang Chai2
1. School of Energy, Power and Mechanical Engineering, North China Electric Power University2. Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology
摘 要：Microstructure, martensitic transformation behavior, mechanical and shape memory properties of Ni56-x Mn25 Fex Ga19（x = 0, 2, 4, 6, 8） shape memory alloys were investigated using optical microscopy（OM）, X-ray diffraction analysis（XRD）, differential scanning calorimeter（DSC）, and compressive test. It is found that these alloys are composed of single non-modulated martensite phase with tetragonal structure at room temperature, which means substituting Fe for Ni in Ni56 Mn25 Ga19 alloy has no effect on phase structure. These alloys all exhibit a thermoelastic martensitic transformation between the cubic parent phase and the tetragonal martensite phase. With the increase of Fe content, the martensitic transformation peak temperature（Mp） decreases from 356 °C for x = 0 to 20 °C for x = 8, which is contributed to the depressed electron concentration and tetragonality of martensite. Fe addition remarkably reduces the transformation hysteresis of Ni–Mn–Ga alloys. Substituting Fe for Ni in Ni56 Mn25 Ga19 alloy can decrease the strength of the alloys and almost has no influence on the ductility and shape memory property.
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