无序态(Co,Fe)_3V应变-时效硬化的微观机制

TEM STUDY OF MECHANISM OF STRAIN-AGE HARDENING OF INITIALLY DISORDERED (Co, Fe)_3V ALLOY

本文通过透射电镜观察确定:无序态(Co_(78)Fe_(22))_3V合金的应变-时效硬化是由于冷变形位错组织在退火中随着有序化进程转变为特别的位错-层错网络——位错在各{111}面上扩展为层错,通过{111}面相交线上偏位错反应互相连接,发展为以层错四面体为小胞的密集网络,有序态(Co_(78)Fe_(22))_3V合金具有很低的{111}面层错能和相对较高且各向同性的反相畴界能,因此,该合金在高温下维持高强度的微观机制很可能不是Kear-Wilsdof障碍,而是Lomer-Cottrell障碍。

TEM study was made to explore the mechanism of the strain-age hardening of initially-disordered'(Co_(78)Fe_(22))_3V, which was found to be attributed to the formation of a special dislocation-stacking fault configuration in company with disorder-order transformation — dislocations extended to stacking faults on {111} planes and got connected with each other through partial dislocation reaction at intersections of {111} planes, leading to dense networks with cells bounded by stacking fault tetrahedrons. The results also indicated that ordered (Co_(78)Fe_(22))_3V has very low stacking fault energy on {111} planes and relative high and isotropic antiphase boundary energy, which implies that it is most likely to be Lomer-Cottrell locks, not Kear-Wilsdof locks, that are responsible for the high strength at high temperatures of this alloy.