CAJ | 학술논문

采用力学性能测试和透射电镜观察的方法，研究2099铝锂合金不同时效状态下的拉伸性能、应力腐蚀性能以及微观组织。结果表明：在欠时效条件下，合金抗拉强度、屈服强度和伸长率分别为453 MPa、382 MPa和12.5%，基体中形成大量的δ′相；峰时效条件下，大量的T1相以及少量的θ′相在基体中析出，晶界上生成一定数量的第二相，并形成无沉淀析出区，合金相应的抗拉强度、屈服强度和伸长率分别为613 MPa、581 MPa和7.9%；过时效条件下，合金抗拉强度、屈服强度和伸长率分别为610 MPa、570 MPa和7.8%，其微观组织与峰时效合金的相似。在欠时效合金中，由于晶界上残余AlCuFeMn相的存在，从而导致合金具有较高的应力腐蚀敏感性；在峰时效合金中，由于大量的 T1相在基体中析出，促使合金获得理想的抗应力腐蚀性能，强度损失率为0.8%；过时效合金具有与峰时效合金相近的抗应力腐蚀性能。
채용역학성능측시화투사전경관찰적방법，연구2099려리합금불동시효상태하적랍신성능、응력부식성능이급미관조직。결과표명：재흠시효조건하，합금항랍강도、굴복강도화신장솔분별위453 MPa、382 MPa화12.5%，기체중형성대량적δ′상；봉시효조건하，대량적T1상이급소량적θ′상재기체중석출，정계상생성일정수량적제이상，병형성무침정석출구，합금상응적항랍강도、굴복강도화신장솔분별위613 MPa、581 MPa화7.9%；과시효조건하，합금항랍강도、굴복강도화신장솔분별위610 MPa、570 MPa화7.8%，기미관조직여봉시효합금적상사。재흠시효합금중，유우정계상잔여AlCuFeMn상적존재，종이도치합금구유교고적응력부식민감성；재봉시효합금중，유우대량적 T1상재기체중석출，촉사합금획득이상적항응력부식성능，강도손실솔위0.8%；과시효합금구유여봉시효합금상근적항응력부식성능。
Tensile properties, stress corrosion properties and microstructures of 2099 Al-Li alloy under different aging conditions were investigated by mechanical tests and TEM. The results show that, under the under-aged condition, the tensile strength, yield strength and elongation of alloy are 453 MPa, 382 MPa and 12.5%, respectively, and many δ′phases form in the alloy. Under the peak-aged condition, a great number of T1 phases as well as a few of θ′ phases precipitate in the matrix, some secondary phases precipitate along the grain boundaries and the precipitation free zone form, the corresponding tensile strength, yield strength and elongation of alloy are 613 MPa, 581 MPa and 7.9%, respectively. Under the over-aged condition, the tensile strength, yield strength and elongation of alloy are 610 MPa, 570 MPa and 7.8%, respectively, and the microstructures are similar to that of peak-aged alloy. Remained AlCuFeMn phases at grain boundaries result in high SCC susceptibility of under-aged alloy. Peak-aged alloy obtains desirable stress corrosion resistance because many T1 phases precipitate in the matrix, and the strength loss rate is 0.8%. Over-aged alloy obtains similar stress corrosion resistance as peak-aged alloy.