RE-Fe-B(RE=Pr,Nd)铸锭热形变机理的探讨

DISCUSSION ON HOT DEFORMATION MECHANISM OF RE-Fe-B ( RE=Pr,Nd ) INGOTS

在变形温度为85C～1050℃,变形速率为1×10^(-3)～1s^(-1)的条件下,利用热变形模拟试验机,测量了感应熔炼的Pr_(36.5)Fe_(61.2)B_(0.δ)Cu_(1.5)(％)铸锭和Nd_(34.3)Fe_(64.7)B_(1.0)(％)铸锭的应力—应变曲线。分析表明,Pr-Fe-B-Cu铸锭与Nd-Fe-B铸锭的热形变形为与机理是基本一致的,其热形变行为类似于纯金属,其热形变机理与空位扩散的作用有关。铸锭的塑性取决于变形温度(T)和变形速率(?),若T不够高或(?)不够低,则指数律破碎现象不可避免。铸锭在热形变后获得的织构,看来与晶粒中出现的沿基面的位错扩散滑移有关。

Pr36.5Fe61.2B0.8Cu1.5(%) and -Nd34.3Fe64.7B1.0 (%) ingots were prepared by induction melting in an argon atmosphere. The ingots were hot deformed within 850-1050 ℃ and with a strain rate from 1 ×10-3/s to 1/s. Based on the obtained stress strain curves, we suggested that the hot deformation behavior and mechanism of both Pr-Fe-B-Cu and Nd-Fe B ingot are the same in essence. The hot deformation behavior of RE-Fe-B ( RE = Pr, Nd ) ingot is similar to pure metal. The deformation mechanism is related to the role of vacancy diffusion, The plasticity of ingot depends on both temperature (T) and strain rate(e ). If T is not higher enough or e is not lower enough, power law break down is unavoidable. The texture formation in ingot after hot deformation appears to be associated with the presence of diffusion controlled dislocation glide along basal plane in crystals.