激光粉末沉积AlSi10Mg合金的致密化机制

Densification mechanism of AlSi10Mg alloy prepared by laser powder deposition

为提高激光粉末沉积(LPD)制备AlSi10Mg合金的致密度,利用田口方法进行了激光粉末沉积AlSi10Mg合金实验设计,研究了激光能量密度对AlSi10Mg合金致密度的影响,获得了LPD制备高致密度AlSi10Mg合金的能量密度阈值范围。采用扫描电子显微镜(SEM)分析了氧化对激光粉末沉积AlSi10Mg合金致密化的影响,并揭示了LPD制备AlSi10Mg合金的致密化机制。结果表明:激光能量密度在120~140 J/mm^(3)之间时,可以获得高致密的AlSi10Mg合金,致密度在98%以上;氧化膜的存在将降低AlSi10Mg熔液在已沉积层表面的润湿性,熔池内AlSi10Mg熔液不能完全铺展开,导致形成孔洞等缺陷;高激光能量密度可破碎已沉积在AlSi10Mg层表面的氧化膜,使AlSi10Mg熔液能够在已沉积层表面完全铺展。

To improve the densification of AlSi10Mg alloy fabricated by laser powder deposition(LPD), the Taguchi method for the experimental design of laser powder deposition of AlSi10Mg alloy was carried out, the effect of laser energy density on densification of AlSi10Mg alloy was investigated. The threshold range of energy density of high density AlSi10Mg alloy prepared by LPD was obtained. The effect of oxidation on the densification of the LPD AlSi10Mg alloy was analyzed by scanning electron microscope(SEM), and the densification mechanism of AlSi10Mg alloy prepared by LPD was revealed. The results show that high densification AlSi10Mg alloy can be obtained when the laser energy density was between 120 J/mm^(3) and 140J/mm^(3), of which the densification of LPD AlSi10Mg alloy was more than 98%. The existence of oxide film will reduce the wettability of AlSi10Mg melt on the surface of deposited layer, and the AlSi10Mg melt in the molten pool cannot be fully spread, resulting in the formation of holes and other defects. High laser energy density can break the oxide film on the surface of the deposited AlSi10Mg layer, so that the AlSi10Mg melt can be fully spread on the surface of the deposited layer.