多向压缩与退火处理对TA2工业纯钛力学性能的影响

Influence of multi-directional compression and annealing treatment on mechanical properties for TA2 industrial pure titanium

为改善TA2纯钛的力学性能,对粗晶TA2纯钛试样进行多向压缩和退火处理,通过透射电镜微观组织观察、纳微压痕硬度测试、室温拉伸测试及扫描电镜断口形貌观测等手段,对比了粗晶试样、多向压缩试样和不同温度退火试样的组织、硬度、拉伸性能及断口形貌。结果表明:粗晶试样经多向压缩后,晶粒由45μm细化至约200 nm,抗拉强度提升了73.3%,拉伸断口观察到数量少且深度浅的韧窝。当退火温度低于400℃时,多向压缩试样的晶粒未明显生长,仍保持良好的综合力学性能。随着退火温度升高,拉伸断口的韧窝数目增多且深度变深;当退火温度为500℃时,晶粒生长,抗拉强度及硬度快速下降,伸长率大幅提升。

In order to improve the mechanical properties of TA2 pure titanium,the multi-directional compression and annealing treatment was carried out on the coarse grain TA2 pure titanium samples,and the microstructures,hardness,tensile properties and tensile fracture morphologies of coarse grain samples,multi-directional compression samples and annealed samples at different temperatures were compared by means of transmission electron fracture morphology observation,micro-nano indentation hardness test,tensile test at room temperature and scanning electron microscope fracture morphology observation.The results show that after multi-directional compression of coarse grain samples,the grain size is refined from 45μm to 200 nm,the tensile strength is increased by 73.3%,and there are less and shallower dimples obtained in the tensile fracture.When the annealing temperature is below 400℃,the grains of multi-directional compression samples do not grow obviously,and the mechanical properties are kept at a high level.With the increasing of annealing temperature,the number of dimples on the tensile fracture is increased and the depth of dimples is deepened.When the annealing temperature is 500℃,the grain grows,the tensile strength and hardness are decreased rapidly and the elongation is greatly improved.