定向凝固多晶铁磁形状记忆合金力-温度耦合的实验研究

Experimental Studies of Ferromagnetic Shape Memory Alloy under the Force-temperature Coupling

铁磁形状记忆合金兼具大输出应变与高响应频率等综合特性,是新一代驱动与传感材料。采用定向凝固技术制成的多晶铁磁形状记忆合金具有较多优越的力学性能。本文对温度和应力耦合作用下的定向凝固多晶铁磁形状记忆合金的力学特性进行了实验测试,分别获得了定向凝固多晶Ni-Mn-Ga试样在不同恒定温度时的应力-应变循环曲线,以及试样在压缩时两个互相垂直方向的数字散斑图。结果表明:同一恒定温度时,随着应力循环次数的增加,其应变值逐渐减小;同一压缩应力时,不同温度作用过程中定向凝固方向的应力,随着温度的升高逐渐减小。本文结果可为铁磁形状记忆合金在工程中的应用提供一定的指导作用。

Ferromagnetic shape memory alloy,which exhibits large output strain and high response frequency and other comprehensive features,is a new generation of driving and sensing materials.Polycrystalline ferromagnetic shape memory alloy made by directional solidification technology has more excellent mechanical properties. Mechanical characteristics of polycrystalline ferromagnetic shape memory alloy made by directional solidification technology were experimentally measured under force-temperature coupling.Stress-strain curves of polycrystalline Ni-Mn-Ga made by directional solidification technology at different temperatures and the digital speckle patterns of compressed samples along two perpendicular directions were obtained,respectively.Results indicate that at same constant temperature,the strain value decreases with the increase of stress cycle number;under same compression stress,the stress along directional solidification direction at different temperatures decreases with the increase of temperature. Above results may provide some guidance for ferromagnetic shape memory alloy engineering application.