加工方式对铪棒组织与性能的影响

Effect of Processing Method on Microstructure and Properties of Hafnium Bars

采用热轧和热轧加冷旋锻2种方式将铪棒坯加工成13. 3 mm的铪棒,并对其进行740℃×1 h的真空退火处理,对比研究2种加工方式下铪棒的显微组织、拉伸性能及断口形貌。结果表明,加工率相同时,未退火状态下的热轧加冷旋锻样品的室温及高温抗拉强度、屈服强度明显大于热轧样品,但塑性较低,断口韧窝大而浅;经过740℃真空退火后,热轧加冷旋锻样品的室温及高温抗拉强度、屈服强度略高于热轧样品,屈强比明显增大,断口韧窝大小、深浅与热轧样品接近。铪棒热加工后进行一定程度的冷加工,有利于后期得到更优异的拉伸性能。

The hafnium rod blanks were processed into φ13.3 mm hafnium bars by hot rolling and hot rolling plus cold forging respectively,and then vacuum annealed at 740℃×1 h.The microstructure,tensile properties and fracture morphology of the hafnium bars prepared by these two methods were compared.The result shows that at the same processing rate,the room temperature and high temperature tensile strength and yield strength of the hot-rolled and cold-forged samples in the unannealed state are significantly higher than hot-rolled samples,but the plasticity is lower.The fracture dimples are large and shallow.The room temperature and high temperature tensile strength and yield strength of the hot-rolled and cold-forged samples are slightly higher than hot-rolled samples after vacuum annealing at 740℃,the yield ratio is significantly increased,the size and depth of fractured dimples are approach to the hot-rolled samples.Increasing the certain degree of cold working on the hafnium bar is benefit to obtain better tensile properties in the later stage.