论文部分内容阅读
利用DSC、X射线衍射 (XRD)、透射电镜 (TEM)和能谱分析研究了快速凝固Al 5Zn 2 5Mg 2 5Mn(质量分数 )合金急冷态和退火态的显微组织 ,同时测定了该合金的硬度。DSC曲线有四个放热峰 ,位于 90~ 110℃、2 6 0℃、4 6 0℃和 4 80℃ ,它们分别对应于 η相 (MgZn2 )、T相 (Al2 Mg3Zn3)、Al3Mn相和Al6 Mn相的析出或转变 ,分析结果与XRD和TEM分析一致。研究还表明 :快凝合金急冷态组织为过饱和Al基固溶体 ,无其它相存在 ;快凝合金经 30 0℃× 1h处理后 ,出现 η和T相 ,此时无Al Mn相出现 ;快凝合金经 5 0 0℃× 1h处理后 ,出现了Al Mn弥散相 ,而 η和T相溶入固溶体 ,Al的点阵常数和合金硬度变化验证了上述显微组织的演化过程。随着Al Mn相的析出或转变 ,合金硬度显著提高
The microstructures of rapidly solidified and annealed Al 5 Zn 2 5Mg 2 5Mn (mass fraction) alloys were investigated by DSC, XRD, TEM and EDS. hardness. The DSC curve has four exothermic peaks at 90-110 ° C, 260 ° C, 460 ° C and 480 ° C, respectively corresponding to η phase (MgZn2), T phase (Al2Mg3Zn3), Al3Mn phase and Al6 Mn phase precipitation or transformation, the analysis results and XRD and TEM analysis. The results also show that the rapidly solidified rapidly quenched microstructure is supersaturated Al-based solid solution without any other phases. When the rapidly-solidified alloy is treated at 300 ℃ for 1h, η and T phases appear, and no Al-Mn phase appears. After the alloy was treated at 500 ℃ for 1h, the Al Mn dispersed phase appeared, while the η and T phase dissolved into the solid solution. The lattice constants and alloy hardness changes of Al confirmed the evolution of the above microstructure. With the precipitation or transformation of the Al Mn phase, the hardness of the alloy is significantly increased