论文部分内容阅读
采用铸锭冶金法制备了Al-8.0Zn-2.0Mg-1.2Cu-0.15Zr-xSc合金,对合金进行了固溶、时效处理,测试了不同状态下合金的力学性能和电导率,利用光学显微镜、扫描电镜和透射电子显微镜研究了合金不同状态的显微组织。结果表明:添加微量钪形成的一次Al3(Sc,Zr)相可作为异质形核核心,细化合金铸态组织;均匀化退火过程中析出的二次Al3(Sc,Zr)粒子强烈钉扎位错和亚晶界,有效阻碍固溶处理过程中合金的再结晶;含0.30%Sc的Al-Zn-Mg-Cu-Zr合金的抗拉强度和伸长率显著高于不加钪的铝合金,经一般固溶及回归再时效(RRA)处理后含0.30%Sc合金的抗拉强度提高36 MPa、屈服强度提高30 MPa、伸长率提高3.0%;采用470℃×60 min+485℃×60 min强化固溶处理,降低合金固溶态的电导率,将合金固溶态以及T6态的抗拉强度分别提高了79.6 MPa、55.8 MPa。
Al-8.0Zn-2.0Mg-1.2Cu-0.15Zr-xSc alloy was prepared by ingot metallurgy. The alloy was solution-treated and aged. The mechanical properties and electrical conductivity of the alloy were tested under different conditions. , Scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the primary Al3 (Sc, Zr) phase formed by adding trace amount of scandium can be used as the heterogeneous nucleation center to refine the as-cast microstructure of the alloy. The secondary Al3 (Sc, Zr) particles precipitated during homogenization annealing are strongly pinned Dislocation and subgrain boundaries, which effectively hinder the recrystallization of the alloy during the solution treatment. The tensile strength and elongation of Al-Zn-Mg-Cu-Zr alloy containing 0.30% Sc are significantly higher than that of the aluminum alloy without scandium , The tensile strength of 0.30% Sc alloy increased by 36 MPa, the yield strength increased by 30 MPa, and the elongation increased by 3.0% after treated by RRA. The elongation at 470 ℃ × 60 min + 485 ℃ × After 60 min, the solid solution treatment decreased the conductivity of the alloy in solid solution state and increased the solid solution state and T6 tensile strength by 79.6 MPa and 55.8 MPa, respectively.