定向凝固Tb-Dy-Fe合金的热处理组织与性能

采用区熔定向凝固的方法,制备〈110〉取向Tb-Dy-Fe超磁致伸缩合金晶体.用管式炉氩气保护,在900-1100℃进行4和48 h的均匀化热处理,研究了热处理对Tb-Dy-Fe合金取向、组织、磁致伸缩性能和力学性能的影响.结果表明,热处理不改变Tb-Dy-Fe合金的轴向择优取向;热处理4 h后,网状富稀土相明显退化,向颗粒状转变;热处理48 h后,网状富稀土相基本消失,形成大量颗粒状富稀土相.热处理明显提高了Tb-Dy-Fe合金样品的磁致伸缩性能,特别是提高低场磁致伸缩性能,但力学性能下降.经4 h热处理,本实验条件下制备的〈110〉取向Tb-Dy-Fe合金样品综合性能最好.

MICROSTRUCTURE AND PROPERTIES OF THE HEAT TREATED DS Tb--Dy--Fe ALLOY

<110> oriented rods of a Tb--Dy--Fe magnetostrictive alloy have been successfully prepared by zone melting unidirectional solidification. A homogenization annealing for 4 or 48 h at 900---1100 C has been carried out in a quartz cylinder under Ar protection after pumping to 2X10 -3 Pa. It was found that, after annealing, <110> preferred orientation is unchanged, the net shape pseudo--eutectic rare earth phase trends discontinuous and spheroidal, magnetostriction slightly decreased without pre--stress but increased obviously with pre--stress. An obvious magnetostriction jump effect was observed in the annealed samples. A satisfactory magnetostrictive property of 1950X10 -6 was obtained under 15 MPa pre--stress after 4 h heat treatment. The compressive stresses of the heat--treated samples decrease monotonously with increasing the soaking time. A satisfactory combination of the magnetostriction and mechanical properties was obtained at annealing for 4 h for the <110> oriented Tb--Dy--Fe alloy.