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采用光学显微镜(OM)、电子探针(EPMA)、波谱仪(WDS)、室温力学性能拉伸和硬度测试等方法,对新型Al-4.3Cu-1.4Mg-0.6Mn-0.1Ce合金的最佳热处理工艺进行了探究。结果表明,该合金的铸态组织中由于Ce、Cu原子的交互作用而存在严重的枝晶偏析,经420℃×8 h+490℃×20 h的双级均匀化处理后,合金内部偏析基本消除,只有少量的非平衡相Al_2CuMg和高熔点相Al_8Cu_4Ce和Al_7Cu_2Fe。当固溶温度为500℃时,固溶效果最佳,且合金没有发生明显的再结晶晶粒长大现象。合金经160~190℃的高温短时人工时效后,硬度变化不大,为117 HBW。经180℃×1 h高温短时人工时效处理后合金的抗拉强度为449.20 MPa,与自然时效状态下的抗拉强度(447.66 MPa)相差不大,但伸长率高出3个百分点。
The best Al-4.3Cu-1.4Mg-0.6Mn-0.1Ce alloy was obtained by optical microscope (OM), electron probe (EPMA), spectrometer (WDS), tensile testing of mechanical properties at room temperature and hardness test. Heat treatment process was explored. The results show that there exists severe dendritic segregation in the as-cast microstructure of the alloy due to the interaction between Ce and Cu atoms. After being homogenized at 420 ℃ for 8 h and 490 ℃ for 20 h, the internal segregation of the alloy Elimination, only a small amount of non-equilibrium phase Al 2 CuMg and high-melting phase Al_8Cu_4Ce and Al_7Cu_2Fe. When the solution temperature is 500 ℃, the effect of solid solution is the best, and the recrystallized grain growth does not occur obviously in the alloy. After 160 ~ 190 ℃ high temperature short-term artificial aging, the hardness changes little, 117 HBW. The tensile strength of the alloy after short-time artificial aging at 180 ℃ × 1 h was 449.20 MPa, which was almost the same as that of natural aging (447.66 MPa), but the elongation was 3% higher.