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通过力学性能检测、DSC热分析、金相显微镜和扫描电镜观察研究了经过双级均匀化和强热变形工艺的2D70铝合金挤压棒材固溶处理温度和时间对合金组织与电导率的影响。结果表明,合金经过固溶处理后可溶第二相已基本溶入基体中,残余的高熔点难溶相主要为近球形白色高亮度Al7Cu4Ni相和灰色块条状、棒状或球状Al9FeNi相;随着固溶温度升高,材料强度、硬度和伸长率都呈上升趋势,电导率则呈下降趋势,但性能曲线随固溶温度变化相对平缓,合金较为理想的固溶处理温度为535~545℃。随着固溶时间的延长,显微组织变化不明显,强度呈上升趋势,固溶120 min时强度和硬度都达到峰值,分别是440 MPa和140 HB,此时伸长率为12%,随固溶时间延长电导率总体变化不大。
The effects of solution treatment temperature and time on the microstructure and electrical conductivity of 2D70 aluminum alloy extruded rod after two-stage homogenization and hot deformation were investigated by mechanical properties testing, DSC thermal analysis, optical microscope and scanning electron microscope. . The results show that the soluble second phase has basically dissolved into the matrix after solution treatment, and the residual high melting point insoluble phase is almost spherical white bright Al7Cu4Ni phase and gray bar, rod or spherical Al9FeNi phase. With the increase of solution temperature, the strength, hardness and elongation of the material all showed an upward trend while the conductivity decreased. However, the change of the performance curve with the solution temperature was relatively slow. The optimum solution temperature for the alloy was 535-545 ℃ . With the extension of solution time, the microstructure did not change obviously, and the strength tended to increase. The strength and hardness peaked at 120 min in solid solution, which were 440 MPa and 140 HB, respectively. The elongation at this time was 12% Prolonged solution time Conductivity generally did not change much.