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研究了损伤容限型TC21钛合金在不同热处理过程中的组织演化及显微组织对力学性能的影响。结果表明,锻后空冷并经(900°C,1 h,AC)+(590°C,4 h,AC)热处理,能获得较佳的综合性能。单相区变形,β晶粒呈盘状;单相区退火,β晶粒呈等轴状。单相区变形或退火后的冷却速率及两相高温区退火决定粗大α片的含量及形貌;经过时效或第三次退火后,细小的次生α片从残留β基体中析出。合金的抗拉强度和屈服强度随着粗大α片含量的增加而降低。低的有效滑移长度和高的裂纹扩展阻力能提高合金的室温塑性。交叉分布的粗大α片厚度的增加,有助于提高合金的断裂韧性。
The effects of microstructure and microstructure evolution on the mechanical properties of the TC21 titanium alloy subjected to different heat treatments were studied. The results show that after forging air cooling and heat treatment (900 ° C, 1 h, AC) + (590 ° C, 4 h, AC), better overall performance can be obtained. Single-phase zone deformation, β-plate was disc-shaped; single-phase annealing, β-grain was equiaxed. After single-phase zone is deformed or annealed, the cooling rate and annealing in the two-phase high temperature zone determine the content and morphology of the coarse α-plate. After the aging or the third annealing, the fine secondary α-platelet precipitates from the residual β matrix. Tensile strength and yield strength of the alloy decreased with the increase of the content of coarse α. Low effective slip length and high crack propagation resistance can improve the room temperature ductility of the alloy. The cross-distribution of coarse α-sheet thickness increases, helping to improve the fracture toughness of the alloy.