时效处理对5A06铝合金压铸件组织和力学性能的影响

通过光学显微镜(OM),扫描电镜(SEM)及拉伸试验等研究了时效处理对5A06铝合金压铸件组织与性能的影响。结果表明:随着时效温度升高,合金压铸件的抗拉强度呈现先上升后下降的趋势,伸长率先降低后升高,最佳时效温度为240℃;在240℃时效过程中,合金压铸件的综合力学性能随着时效时间的延长呈现先上升后趋于平稳的趋势,最佳时效工艺为240℃×4 h,此时合金力学性能得到明显改善,抗拉强度提高了10.43%,伸长率略微降低,其强化机理主要为时效过程中进一步析出的β(Al₈Mg₅)相的第二相强化。时效处理后合金压铸件的断裂方式依旧为准解理断裂。

Effect of aging treatment on microstructure and mechanical properties of 5A06 aluminum alloy castings

Effect of aging treatment on microstructure and properties of 5 A06 aluminum alloy castings was studied by means of optical microscope,scanning electron microscopy and tensile test.The results show that with the increase of aging temperature,the tensile strength of the alloy castings increases first and then decreases,the elongation decreases first and then increases,and the optimum aging temperature is 240℃.During aging at 240℃,the comprehensive mechanical properties of the alloy castings increase first and then tend to stabilize with the increase of aging time,the optimum aging process is aging at 240℃for 4 h,at this time,the mechanical properties of the alloy castings are obviously improved and the tensile strength is increased by 10.43%,the elongation decreases slightly,and the strengthening mechanism is mainly theβ(Al₈Mg₅)second phase strengthening.The fracture mode of the alloy castings after aging treatment is still quasi-cleavage fracture.