退火态ZTi6Al4V铸造钛合金的断裂韧度研究

将尖切口强度理论用于ZTi6Al4V铸造钛合金损伤容限性能的评价,探讨了不同退火温度对其三点弯曲断裂韧度KQ的影响。结果表明:尖切口试样测定的断裂韧度KQ1不等同于标准试验方法测定的KQ,但可用于铸造钛合金不同工艺间断裂韧度的比较。退火温度的改变可微调ZTi6Al4V铸造钛合金的强度和断裂韧度,在700℃或820℃保温2h退火处理,试样的断裂韧度较好,KQ值分别达到78.11 MPa.m1/2和79.44MPa.m1/2,屈服强度分别为782.74MPa和771.49MPa,抗拉强度分别为860.18MPa和853.0MPa,伸长率达8.10%和7.46%,获得了较好的强塑性匹配。

Fracture Toughness of ZTi6Al4V Casting Titanium Alloy under Different Annealed Conditions

The theory of notch strength was used to judge the damage tolerance capability of ZTi6Al4V casting titanium alloy,for example,the effect of annealing temperature on three-point bending fracture toughness.The results show that fracture toughness KQ1,which was tested by notched specimens,is not equal to the KQ tested by the standard testing method.But it was used to compare qualitatively fracture toughness of casting titanium alloy with different annealing processes.The changing of annealing temperature can adjust strength and fracture toughness of ZTi6Al4V casting titanium alloy.Samples annealed at 700℃and 800℃ for 2h have better toughness,the KQ values are 78.11 MPa·m1/2 and 79.44MPa ·m1/2.They also have a relatively better match of strength and plasticity,that is the yield strength is up to 782.74MPa and 771.49MPa,tensile strength reaches 860.18MPa and 853.0MPa,and the elongation reaches 8.10% and 7.46% respectively.