(山东大学 材料液固结构演变与加工教育部重点实验室 材料连接技术研究所，济南 250061)
摘 要: 本文研究了工艺参数对不锈钢表面增材制造铝青铜薄壁试样组织和性能的影响。结果表明：基材与熔敷层之间形成了一层Fe基固溶体层，附近熔敷层中离散分布Fe基固溶体粒子和FeAl3相；随着送丝速度的增大，Fe基固溶体层的厚度增大，粒子大小、数量及分布范围均增大。剪切时裂纹并未一直沿着结合界面层扩展，而主要是从熔敷层断裂；剪切强度随着送丝速度增大而增大。第二层以上每道熔敷层的组织分为三部分，垂直于交界线的粗大柱状晶、偏离垂直方向生长的细小柱状晶以及由等轴晶和水平生长的柱状晶组成的混合区。送丝速度对薄壁试样强度的影响较小，横向拉伸强度为390 MPa左右，纵向为360 MPa左右，断裂形式均为韧性断裂。
关键字: 冷金属过渡；增材制造；显微组织；力学性能
（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
