热处理冷却速率与Cr掺杂对Heusler合金Mn50-xCrxNi40In10相变、磁性以及磁热效应的影响

Influence of cooling rate of heat treatment and Cr doping on the phase transformation,magnetic property and magnetocaloric effect of Mn50-xCrxNi40In10 Heusler alloys

本文采用电弧熔炼方法制备了两组Mn50-xCrxNi40In10(x=0,1,2)多晶系列样品,通过改变热处理的冷却速率与Cr掺杂量对样品的相变、磁性以及磁熵变进行了研究。结果表明,与淬火样品相比,慢冷合金的马氏体相变温度较高。随着Cr含量的增加,奥氏体的磁化强度逐渐降低,而马氏体的磁化强度逐渐增强。与淬火样品相比,慢冷样品在相变温度附近,奥氏体和马氏体的磁化强度增强。这主要是由于慢冷样品的原子有序度较高,从而导致其较高马氏体相变温度以及强磁性。不同的热处理冷却速率对Mn49Cr1Ni40In10合金的磁熵基本没有影响。此外,施加3 T磁场时,在Mn49Cr1Ni40In10合金中观察到约为13 J/(kg·K)的大的熵变。

In this paper,two sets of Mn50-xCrxNi40In10(x=0,1,2)polycrystalline samples were prepared by arc melting.The phase transformation,magnetic properties and magnetic entropy changes of the samples were studied by changing the cooling rate of heat treatment and the content of Cr.It is shown that the martensitic transformation temperature of the slow-cooled alloy is higher than that of the quenched sample.As the Cr content increases,the magnetization of austenite gradually decreases,while the magnetization of martensite gradually increases.Compared with the quenched sample,the magnetization of the slow-cooled sample for both austenite and martensite states are enhanced.This is mainly attributed to the improvement of the atomic order degree in slow-cooled sample.The cooling rate nearly has no effect on the magnetic entropy change of the Mn49-Cr1Ni40In10 alloy.In addition,when a 3 T magnetic field was applied,a large entropy change was observed in the Mn49Cr1Ni40In10 alloy,which is about 13 J/(kg·K).