超声铸造2219铝合金均匀化工艺及第二相演变

Homogenization process and the second phases evolution of 2219 aluminium alloy treated by ultrasonic

采用DSC、金相、扫描电镜及能谱分析等方法,研究超声铸造2219铝合金均匀化工艺及合金铸锭中的第二相在不同均匀化制度处理过程中的演变规律。研究结果表明:超声铸造2219铝合金铸锭中存在大量非平衡凝固共晶体,其中的低熔点非平衡共晶相为Al_2Cu相,其过烧温度为560.79℃;在均匀化热处理过程中,该非平衡凝固共晶体不断向合金基体溶解,其数量、形态和分布均发生很大变化;铸锭中还存在少量长条状含铁相,该相在某些均匀化制度处理下变得粗大;该合金较合理的均匀化制度为550℃,24 h。

Homogenization process and the second phases evolution of 2219 aluminium alloy treated by ultrasonic were studied by DSC, optical microscope, scanning electron microscopy and EDS. The results show that 2219 aluminium alloy treated by ultrasonic exhibits a large number of non-equilibrium eutectics, and its lower melting point eutectic is Al2Cu phase, of which the overburn temperature is 560.79 ℃. With the increase of hemogenizing temperature, Al2Cu phases are gradually dissolved into Al matrix, and great changes take place in their quantity, morphology and distribution. There is also a small amount iron-bearing phases, which becomes larger during homogenizing. Fairly reasonable homogenizing treatment of 2219 aluminium alloy treated by ultrasonic is at 550 ℃ for 24 h.