(山東大學(xué) 材料液固結(jié)構(gòu)演變與加工教育部重點實驗室 材料連接技術(shù)研究所，濟南 250061)
摘 要: 本文研究了工藝參數(shù)對不銹鋼表面增材制造鋁青銅薄壁試樣組織和性能的影響。結(jié)果表明：基材與熔敷層之間形成了一層Fe基固溶體層，附近熔敷層中離散分布Fe基固溶體粒子和FeAl3相；隨著送絲速度的增大，F(xiàn)e基固溶體層的厚度增大，粒子大小、數(shù)量及分布范圍均增大。剪切時裂紋并未一直沿著結(jié)合界面層擴展，而主要是從熔敷層斷裂；剪切強度隨著送絲速度增大而增大。第二層以上每道熔敷層的組織分為三部分，垂直于交界線的粗大柱狀晶、偏離垂直方向生長的細小柱狀晶以及由等軸晶和水平生長的柱狀晶組成的混合區(qū)。送絲速度對薄壁試樣強度的影響較小，橫向拉伸強度為390 MPa左右，縱向為360 MPa左右，斷裂形式均為韌性斷裂。
關(guān)鍵字: 冷金屬過渡；增材制造；顯微組織；力學(xué)性能
（Key Laboratory for Liquid-Solid Structure Evolution and Materials Processing, Ministry of Education, Institute for Materials Joining, Shandong University, Jinan 250061, China）
Abstract:The effect of process parameters on microstructure and properties of additive manufactured Cu-Al bronze on St-St substrate was studied. The results show that a continuous layer of Fe-based solid solution forms between the substrate and the deposit. In addition, isolated particles composed of Fe-based solid solution and FeAl3 are distributed in the additive manufactured Cu-Al Cu matrix. The thickness of the Fe-based solid solution layer and the particle size and number increase with increasing wire feed speed. The shear strength between the substrate and deposit increases with the increase of wire feed speed. The shear fracture does not propagate along the Fe-based solid solution layer, but goes through the deposited metal near the substrata. The microstructure of each deposited pass above the second layer are divided into three zones, i.e. coarse columnar grain zone, fine columnar grain zone and mixed zone consisting of equiaxed and horizontal columnar grains. The wire feeding speed has little effect on the mechanical strength of thin-walled specimen. The transverse tensile strength is about 390 MPa and the longitudinal one is about 360 MPa. All the fracture surfaces exhibit dimple structure.
Key words: cold metal transfer; additive manufacturing; microstructure; mechanical property
