【摘要】 Ti25V15Cr0.3Si合金含有40%左右的合金元素,是一种高固溶强化的β钛合金。测试了Ti25V15Cr0.3Si合金在室温(25℃)至600℃下的裂纹扩展性能,发现随着温度升高,裂纹扩展速率增大。与Ti6Al4V和β21S合金相比,室温下Ti25V15Cr0.3Si合金的裂纹扩展速率高于Ti6Al4V而低于β21S合金。600℃高温下,Ti25V15Cr0.3Si合金的裂纹扩展速率与β21S在650℃时的水平相当。研究结果表明,合金的屈服强度、弹性模量、断裂韧性、氧化性能和组织结构特征综合影响着Ti25V15Cr0.3Si合金的裂纹扩展损伤行为。从室温到300℃,随温度的升高,Ti25V15Cr0.3Si合金的屈服强度和弹性模量降低同时断裂韧性升高,因此裂纹扩展速率变化不明显;而从500～600℃,温度升高氧化加剧,合金疲劳裂纹扩展速率明显增加。与Ti6Al4V合金相比,室温下,Ti25V15Cr0.3Si合金相对于Ti6Al4V合金具有较低的弹性模量以及等轴的β组织,裂纹扩展速率较高。而与β21S合金相比,Ti25V15Cr0.3Si合金的屈服强度和弹性模量高于β21S合金,因此裂纹扩展速率较低。600℃高温下,Ti25V15Cr0.3Si合金的氧化程度明显高于β21S合金。高温下材料的氧化使得Ti25V15Cr0.3Si合金的裂纹扩展速率只与β21S在650℃时的水平相当。更多还原

【Abstract】 Ti25V15Cr0.3Si alloy was a kind of beta titanium alloy,which was solid solution strengthened by about 40% alloying elements.The crack propagation rates of Ti25V15Cr0.3Si alloy were tested at the temperature from room temperature to 600 ℃.The results showed that the crack propagation rate of Ti25V15Cr0.3Si alloy accelerated when the temperature increased.At room temperature,the crack propagation rate of Ti25V15Cr0.3Si was higher than that of Ti6Al4V but was lower than that of β21S.At high temperature,the crack propagation rate of Ti25V15Cr0.3Si at 600 ℃ was similar to the rate of β21S at 650 ℃.The results indicated that the combined factors,including yield strength,Young′s modulus,fracture toughness,oxidation susceptibility and metallurgical structure,affected the crack propagation damage behaviour of Ti25V15Cr0.3Si alloy.When the temperature increased from room temperature to 300 ℃,the yield strength and Young′s modulus of Ti25V15Cr0.3Si decreased but the fracture toughness grew.The crack propagation rate of Ti25V15Cr0.3Si did not change obviously.When the temperature increased from 300 to 600 ℃,Ti25V15Cr0.3Si alloy was oxidized.The crack propagation rate increased significantly.At room temperature,compared with Ti6Al4V,Ti25V15Cr0.3Si owned equiaxed structure and had lower Young′s modulus than that of Ti6Al4V with lamellar structure.The crack propagation rate of Ti25V15Cr0.3Si was high.Compared with β21S,the yield strength and Young′s modulus of Ti25V15Cr0.3Si were higher than that of β21S,which leaded to a lower crack propagation rate than that of β21S.At 600 ℃ high temperature,Ti25V15Cr0.3Si oxidized heavier than that of β21S,whose propagation rate was almost the same as the rate of β21S at 650 ℃.更多还原