CAJ | 학술논문

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。
연구료손상용한형TC21태합금재불동열처리과정중적조직연화급현미조직대역학성능적영향。결과표명，단후공랭병경(900°C，1 h，AC)+(590°C，4 h，AC)열처리，능획득교가적종합성능。단상구변형，β정립정반상；단상구퇴화，β정립정등축상。단상구변형혹퇴화후적냉각속솔급량상고온구퇴화결정조대α편적함량급형모；경과시효혹제삼차퇴화후，세소적차생α편종잔류β기체중석출。합금적항랍강도화굴복강도수착조대α편함량적증가이강저。저적유효활이장도화고적렬문확전조력능제고합금적실온소성。교차분포적조대α편후도적증가，유조우제고합금적단렬인성。
Microstructure evolutions during different heat treatments and influence of microstructure on mechanical properties of TC21 titanium alloy were investigated. The results indicate that the excellent mechanical properties can be obtained by adopting air cooling after forging followed by heat treatment of (900 °C, 1 h, AC)+(590 °C, 4 h, AC). Deformation in single βfield produces pan-like priorβgrains, while annealing in singleβfield produces equiaxed priorβgrains. Cooling rate after forging or annealing in singleβfield and the subsequent annealing on the top ofα+βfield determine the content and morphology of coarseαplates. During aging or the third annealing, fine secondaryαplates precipitate. Both ultimate strength and yield strength decrease with the content increase of coarse α plates. Decreasing effective slip length and high crack propagation resistance increase the plasticity. The crisscross coarseαplates with large thickness are helpful to enhance the fracture toughness.