The annealing characteristics of pure molybdenum bars manufactured by a modified technique

The annealing characteristics of the forged and upset pure molybdenum bar were investigated by bending measurement, optical microstructure (OM) observation, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the modified forge and upset technique is effective to refine the grains and interpenetrate the fiber structures, which largely improve the transverse ductility of the pure molybdenum bar. For the bar deformed by 85%, recovery is the main behavior at the annealing temperature of 1073 K for 1 h; at 1253–1323 K for 1 h, recrystallization begins; over 1423 K, further recrystallization continues and results in the decrease of transverse ductility. For the pure molybdenum bar with good transverse ductility, its fracture is mainly a transcrystalline fracture type accompanied by little intergranular cracks and some dimples.