【摘要】 对Ti700钛合金在不同热处理制度下的冲击韧性进行了研究。结果表明,Ti700钛合金冲击韧性随退火温度升高而发生明显变化,650~850℃处理后试样的冲击韧度为低值区,915℃处理可获得最高值。相变点以下热处理试样的冲击断口为韧性断裂,相变点以上热处理的为准解理的脆性断裂。915℃试样热处理的初生α相体积分数为12%,随着退火温度的降低,初生α相体积分数升高,尺寸增大,Al元素富集于α相中。初生α相界有利于微裂纹的形核,随着初生α相体积分数减少,避免了在初生α相界处孔洞萌生,可有效改进材料的冲击韧性。更多还原

【Abstract】 The impact toughness of Ti700 titanium alloy under different heat treatments was investigated.The results show that the impact toughness of Ti700 titanium alloy changes significantly with the annealing temperature increasing.The lower toughness values of the alloy fall in the temperature region of 650～850 ℃,while the highest value appears at 915 ℃ treatment.The impact fracture of the specimen treated below transformation point is a type of gliding fracture,while above transformation point it is brittle fracture.The volume fraction of primary α phase heat treated at 915 ℃ is about 12%.With annealing temperature decreasing,the volume fraction and the size of primary α phase increase,meanwhile the aluminum element enriches in the primary α phase.Boundaries of primary α phase are observed to be preferential sites for microcrack nucleation.With volume fraction decreasing,cavity initiation at primary α phase boundaries is prevented,which can improve the impact toughness of the material effectively.更多还原