GdErCoAl非晶合金的玻璃形成能力及磁热效应

Glass formingabilityand magnetocaloric effect of Gd-Er-Co-Al alloys

利用真空甩带机制备了成分为Gd_(56-x)Er_xCo_(24)Al20(x=0,16,24,32,40,48)的一系列非晶条带,并用高真空电弧熔炼炉铜模吸铸法制备了直径为3mm的大块非晶合金棒;然后对合金的结构、热稳定性和磁热效应进行了系统研究。研究结果表明,该系列合金有很好的玻璃形成能力、较高的热稳定性以及高的磁熵变(最大可达12.58J·kg^(-1)·K^(-1))和宽的磁熵变曲线峰。当x从0增加到48时,该系列合金在磁场变化为5T条件下制冷能力(RCP)分别是729J·kg^(-1)、736J·kg^(-1)、757J·kg^(-1)、621J·kg^(-1)、576J·kg^(-1)和435J·kg^(-1)。随Er含量的增加,合金磁转变类型从铁磁转变逐步到自旋玻璃转变,磁转变温度从112K降低到16.5K。Gd56-xErxCo24Al20系列的非晶合金优异的磁制冷能力,连续可调的磁转变温区,良好的热稳定性和软磁性能表明这系列合金在10~150K的范围内做为磁制冷材料拥有良好的应用前景。

Metallic glass ribbons with norminal composition of Gd_（56-x）Er_xCo_（24）Al_（20）（x=0,16,24,32,40,48）were fabricated by melt spinning technique,and rod samples of 3mm in diameter were fabricated by copper-mold suck casting method.The microstructure,thermal properties and magnetocaloric effect of these amorphous alloys were investigated.The results show that these alloys have good glass formation ability,good thermal stability,and large magnetic entropy change（having a maximum value of 12.58J·kg^-1K^-1 under a field change of 5T）.The magnetic entropy change curve has a broadened peak due to the amorphous structure.The refrigeration capacity（RCP）under a field change of 5Tcan be determined to be 729J·kg^-1736J·kg^-1757J·kg^-1621J·kg^-1576J·kg^-1nd435J·kg^-1for the 6samples fromx=0to x=48,respectively.With the increase of Er content,the Curie temperature decreases from 112 Kto 16.5K.Due to the very good magnetocaloric effect,high thermal stability,free of hysteresis and well tunability of the working temperature,this series of alloys can be good candidates as magnetic refrigerants working in the temperature range of 10~150K.