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The φ60 mm hafnium billet was processed to φ13.3 mm by hot rolling and cold rotary forging,and then vacuum annealing was carried out at 440,600,740,900 and 1 040℃for 1 h respectively.The microstructure,room temperature and high temperature tensile properties,high temperature tensile fracture morphology of the hafnium bars under different annealing temperatures were studied comparatively.It is shown that with the increase of annealing temperature,the grain gradually grows,but the twin structure does not completely disappear with the increase of annealing temperature,in contrast,annealed twins are easily developed in the hafnium bar at high temperature;the tensile strength and yield strength of the hafnium bar gradually decrease with the increase of the annealing temperature,with a slow and then fast decline of the tensile strength while the yield strength is otherwise.The tensile fracture morphologies at 440,600 and 740℃present ductile fracture feature with many dimples,whose fracture size and density are slightly different.However,after annealing at 900℃and 1 040℃,the fracture morphologies appear as cleavage steps and river-like pattern,which are brittle fractures.