激光熔覆制备铝硅梯度材料

Aluminum-silicon gradient material prepared by laser cladding

以1050铝合金为基体,利用激光熔覆技术成功制备了从Al-70Si到近乎纯硅的超高硅含量的铝硅梯度材料,观察和分析熔覆层的截面形貌、显微组织、物相组成成分和硬度等。研究结果表明,熔覆层内部组织的分布为最外层初晶硅含量最多,尺寸也最大;从熔覆层表面到基体处,初晶硅的体积分数及尺寸逐渐减少,呈梯度变化。硅颗粒形貌由长条状转变为多边形状,靠近基体处的颗粒趋于圆片状,分析认为硅颗粒形貌的不同是由于温度梯度和凝固快慢不同导致的,与熔池大小和停留时间相关。铝硅梯度材料的硬度分布为最外层硬度较高,由外向内硬度逐渐减少,呈梯度变化。

Al-Si gradient material with silicon content changing gradiently from 70%to 100%using 1050 aluminium alloy as the matrix was successfully prepared by laser cladding technology.Microstructure and properties of laser cladding layer were investigated.The results show that the most primary silicon with the largest size are distributed in the outer layer of the inner structure.From the surface of the cladding layer to the substrate,the volume fraction and size of the primary silicon decrease gradually,showing a gradient change.The morphology of silicon particles were changed from long-shaped to polyg-onal-shaped.As approaching the substrate,the particles tend to be disc-shaped.The different morphology of silicon particles is caused by the different temperature gradient and solidification speed,which is related to the size of molten pool and residence time.The hardness distribution of Al-Si gradient material is that the hardness of the outermost layer is higher.From the outside to the inside,the hardness decreases gradually,showing a gra-dient change.