均匀化处理温度对6082铝合金组织和性能的影响

采用硬度、电导率测试、金相显微镜、X线衍射、扫描电镜、透射电镜和能谱分析技术,研究均匀化温度对合金组织和性能的影响.研究结果表明:铸态合金由α-Al固溶体和非平衡共晶相组成；490～510℃均匀化,Mg2Si相从过饱和固溶体中析出,在510℃以上均匀化,随着温度的升高,Mg2Si又逐步回溶到基体中,560℃均匀化,Mg2Si相和过剩单质Si完全溶解；随着均匀化温度的升高,非平衡析出物鱼骨状共晶形态逐渐消失,针状β-AlMnFeSi溶解、断裂,转变为具有更高(Mn+Fe)/Si比值颗粒状α-Al(MnFe)Si相,析出相在高温均匀化过程中聚集、球化；560℃均匀化,析出物的连续网状结构转变成链状结构,析出物演化为等轴粒状α-Al(MnFe)Si相.均匀化过程中合金中析出弥散α-Al(MnFe)Si相；在490～560℃保温6h均匀化处理,温度升高,合金的硬度和电导率分别升高和降低.

Effect of homogenization treatment temperatures on microstructure and properties of 6082 aluminum alloys

The effect of homogenization treatment temperature on microstructure and properties of 6082 aluminum alloys were investigated by using hardness and electrical conductivity measurement,optical microscope(OM),X-ray diffraction(XRD),scanning electronic microscope(SEM),energy dispersive spectrum(EDS) and transmission electron microscopy(TEM).The results show that the as-cast alloy consists of supersaturated solid solution and unequilibrium eutectic phases.Supersaturated solid solution changes into equilibrium Mg2Si phase at 490-510 ℃;equilibrium phases are dissolved into matrix when the homogenization temperature is higher than 510 ℃;Mg2Si phase and Si phase dissolved into matrix completely at 560 ℃.With the increase of annealing temperature,the eutectic morphology of precipitates disappears gradually,acicular β-AlMnFeSi phase transforms to spherical α-Al(MnFe)Si phase and the ratio of n(Mn+Fe)/n(Si) in AlMnFeSi phase increases.The precipitates is changed into spherical α-Al(MnFe)Si phase after annealing at 560 ℃ for 6 h.During homogenization,dispersive α-Al(MnFe)Si particles deposit in the alloy.The hardness increases and conductivity decreases with the increase of annealing temperature.