新型Al-Cu-Li-X合金热处理强化及组织特征

Heat treatment strengthening and microstructure characteristics of novel Al-Cu-Li-X alloy

采用正交试验及其方差分析、最小显著差数(LSD)法研究新型Al-Cu-Li-Ag-Mg-Zr-Ce合金的固溶和时效热处理工艺,并采用电导率、SEM、EDX、TEM等测试手段对合金热处理过程中组织结构和性能进行分析。结果表明:该合金在固溶(520℃,1.5 h,水冷)和时效(180℃,18 h,空冷)处理后,T6态显微硬度比轧制态的提高100.8%,T87态强度值达到623 MPa。固溶过程中,大量Ce、Cu、Mg、Zr溶于基体起到固溶强化作用;时效时细小片状强化相T1和薄盘状θ′相均匀弥散在基体中析出,具有强烈沉淀强化效果。

Solid solution and aging treatment of novel Al-Cu-Li-Ag-Mg-Zr-Ce alloy was investigated by orthogonal experiment variance analysis and least significant difference(LSD) methods.Meanwhile,the microstructure characteristics and mechanical properties were explored by electrical conductivity(EC) test,scanning electron microscopy(SEM),energy dispersive X-ray spectrum(EDX) and transition electron microscopy(TEM).The results show that the micro-hardness of alloy under T6 condition are improved by 100.8% compared to that of rolling one,and the strength for alloy under T87 condition also reaches to 623 MPa after solid solution(520 ℃,1.5 h,water quenched)and aging treatment(180 ℃,18 h,air quenched).During solid solution,a lager amount of Ce、Cu、Mg and Zr atoms dissolve into the matrix,resulting in a strong solid solution strengthening.During the aging treatment,many fine needle-shaped T1 phase and plate-shaped θ′ phase precipitate in the matrix uniformly and dispersively,leading to an enormous precipitation strengthening.