高强韧再生Al-1.15Mg-1.02Si-0.7Cu合金组织与性能研究

Microstructure and Properties of the Recycled Al-1.15Mg-1.02Si-0.7Cu Alloy with High Strength and Toughness

通过熔炼铸造法制备了再生Al-1.15Mg-1.02Si-0.7Cu合金,使用金相显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)分析了合金显微组织演变,并研究了热处理制度对该合金挤压型材力学性能和耐腐蚀性能的影响。结果表明:在550℃固溶后合金完成了再结晶,获得了细小的等轴晶。合金在155、175、195℃人工时效条件下达到峰值硬度所需的时间分别为18、8、4 h,峰值硬度分别为132.96、132.94和132.22 HV,其中挤压型材在175℃/8 h的时效条件下可获得最高的抗拉强度410.42 MPa和较高的延伸率14.75%。合金较优的固溶工艺为550℃/1 h,较优的人工时效工艺为175℃/8 h。合金晶间腐蚀倾向较为明显,在峰值时效条件下,合金腐蚀最为严重,过时效次之,欠时效则最弱。

In paper,recycled Al-1.15Mg-1.02Si-0.7Cu alloy was optical prepared by melting and casting,the microstructural evolution of the alloy were analyzed by using optical microscopy(OM),scanning electron microscopy(SEM),electron back scattered diffraction(EBSD)and transmission electron microscope(TEM),the effects of heat-treatment on the mechanical and corrosion-resistant properties of the extruded profiles were investigated.The results show that the recrystallization of the alloy was completed by solid solution at 550℃and fine equiaxial crystals were obtained.The time required for the alloys to reach peak hardness under artificial aging conditions at 155,175 and 195℃was 18,8 and 4 h,respectively,and the peak hardnesses were 132.96 HV,132.94 HV and 132.22 HV,respectively,with the extruded profiles obtaining the highest tensile strength of 410.42 MPa and higher elongation of 14.75%under aging conditions at 175℃/8 h.The optimizedsolid solution process is 550℃/1 h,and the artificial aging process is 175℃/8 h.The tendency of the alloy to intergranular corrosion is more pronounced,and the alloy corrodes most severely under peak-aged conditions,followed by over-aged and weakest under-aged.