中文摘要：

采用电弧炉熔炼的方法制备了Mn_（50）Ni_（41-x）Cr_xSn_9合金铸锭.用X射线衍射、振动样品磁强计、综合物性测试系统对材料的结构、相变和磁热效应进行了研究.结果表明,由于价电子浓度的减小,Cr替代Ni使材料的马氏体转变温度降低.Cr的加入使马氏体转变伴随着较大的磁化强度的突变,从而表现出较大的低场磁熵变.Mn_（50）Ni_（41-x）Cr_xSn_9合金以其较大的低场磁热效应、可调的工作温区在磁制冷领域有着潜在的应用.

英文摘要：

Mn50Ni41-xCrxSn9 alloys are prepared by the arc melting method. Their structure, phase transitions, andmagnetocaloric effect were investigated by using x-ray diffraction, vibrating sample magnetometer, and physicalproperty measurement system. The martensitic transformation temperatures decrease with the substitution of Niby Cr, which can be attributed to the decrease of valence electron concentration. The doping of Cr enhances thechange of magnetization across the martensitic transformation, which implies a large magnetocaloric effect. Thelarge magnetic entropy changes and adjustable working temperatures enable Mn50Ni41-xCrxSn9 alloys to have a potential application in magnetic refrigeration.