TA15钛合金高温与室温拉伸性能的研究

Study on Tensile Properties of TA15 Titanium Alloy at High Temperature and Room Temperature

对TA15钛合金棒材进行拉伸性能试验,采用金相显微镜、扫描电子显微镜以及室温拉伸和高温拉伸试验,研究了该合金在室温和高温拉伸后的金相组织和拉伸性能。结果表明:TA15钛合金棒材原始组织为等轴组织,退火后合金的初生α相尺寸减小,βT组织消失,并有细小次生α相均匀分布。随着退火温度的升高,组织变为双态组织,室温下合金强度先下降再升高,塑性呈现出相反趋势,在960℃时强度最高,抗拉强度为1071 MPa,屈服强度为881MPa,在930℃时塑性最佳,断后伸长率为17.5%,断面收缩率为46%。高温拉伸在870℃时强度最高,抗拉强度为258MPa,屈服强度为189 MPa,在960℃时,塑性最高,断后伸长率为280%。不同退火温度下的室温断口形貌大致相同,均为等轴韧窝,高温拉伸断口中同样包含大量的等轴状韧窝,单其韧窝尺寸更大更深,室温与高温拉伸的断口形貌均为韧性断裂特征。

The tensile properties of TA15 titanium alloy bars were tested.The metallographic structure and tensile properties of the alloy after being stretched at room temperature and high temperature were studied by means of metallographic microscope,scanning electron microscope,and room temperature tensile and high temperature tensile tests.The results show that the original structure of TA15 titanium alloy bar is equiaxed.After annealing,the size of the primaryαphase of the alloy decreases,theβT structure disappears,and there is a uniform distribution of fine secondaryαphases.As the annealing temperature increases,the structure becomes a two-state structure,the strength of the alloy at room temperature decreases first and then increases,and the plasticity presents the opposite trend.The strength is highest at 960℃,the tensile strength is 1071 MPa,the yield strength is 881 MPa,and the plasticity is highest at 930℃,the elongation after fracture is 17.5%,and the reduction of area is 46%.The high temperature tensile strength is highest at 870℃,the tensile strength is 258 MPa,the yield strength is 189 MPa,and the plasticity is highest at 960℃,and the elongation after fracture is 280%.The fracture morphology at room temperature at different annealing temperatures is roughly the same,and they are all equiaxed dimples.The high temperature tensile fracture also contains a large number of equiaxed dimples,but the dimple size is larger and deeper,and the fracture morphologies of room temperature and high temperature tensile appearances are all ductile fracture characteristics.