氮气雾化Al-20Si-7.5Ni-3Cu-1Mg-0.25Fe合金粉末形貌及组织

Research on morphological features and microstructures of Al-20Si-7.5Ni-3Cu-1Mg-0.25Fe alloy powders prepared by nitrogen atomization process

采用氮气雾化制备Al-20Si-7.5Ni-3Cu-1Mg-0.25Fe合金粉末,利用激光粒度分析仪、金相显微镜、扫描电子显微镜、X射线衍射仪和热分析仪对合金粉末的粒度分布、组织、形貌、组成相和相演变规律进行研究。结果显示,该氮气雾化粉末的中粒径为29.5μm,形貌多为球形或类球形,在尺寸较大的粉末颗粒表面存在凹坑和卫星球现象,尺寸较小的粉末表面则相对光滑。粉末内部存在块状初晶硅和片状亚稳金属间化合物,这种亚稳金属间化合物在310℃时会分解为稳定的耐热相。

Al-20Si-7.5Ni-3Cu-1Mg-0.25 Fe alloy powder was prepared by nitrogen atomization process.The size,microstructures,morphological features,phases and their transitions of powder were studied by laser particle sizer,optical microscopy,scanning electron microscopy,X-ray diffractometry,and DSC,respectively.The results show that the median size was about29.5μm,the powder had spheric or near spheric shapes.And concaves and satellite particles were observed on the surface of larger powder,while the finer powder had glossy surface.In addition,the analyses also indicated that block Si phases and flake metastable intermetallics existed in this powder,and the latter phase would decompose to stable phases under 310℃.