Yoo Seong-Won, Lee Choon-Man, Kim Dong-Hyeon
Department of Smart Manufacturing Engineering, School of the Smart Manufacturing Engineering, Changwon National University, Changwon 51140, Republic of Korea.
Department of Mechanical Engineering, College of Mechatronics, Changwon National University, Changwon 51140, Republic of Korea.
Materials (Basel). 2023 Jan 5;16(2):535. doi: 10.3390/ma16020535.
Bimetallic structures manufactured by direct deposition have a defect due to the sudden change in the microstructure and properties of dissimilar metals. The laser metal deposition (LMD)-wire arc additive manufacturing (WAAM) process can alleviate the defect between two different materials by depositing the functionally graded material (FGM) layer, such as a thin intermediate layer using LMD and can be used to fabricate bimetallic structures at high deposition rates with relatively low costs using WAAM. In this study, the LMD-WAAM process was performed, and the microstructure of the fabricated bimetallic structure of IN625-SUS304L was investigated. The microstructure of the FGM zone of the LMD-WAAM sample was mainly fine equiaxed dendrite morphologies. In contrast, coarse columnar dendrite morphologies constituted the WAAM zone. The composition of the major alloying elements of the LMD-WAAM sample gradually changed with the height of the deposited layer. The microhardness of the LMD-WAAM sample tended to increase with an increasing Inconel content. In the case of the LMD-WAAM sample, the fracture occurred near the interface between 25% IN625 and 0% IN625; in the WAAM sample, the final fracture occurred in SUS304L near the interface. The tensile strength of the LMD-WAAM samples was inversely proportional to the laser power. The results showed that the LMD-WAAM samples had 8% higher tensile strength than the samples fabricated using only WAAM.
通过直接沉积制造的双金属结构由于异种金属的微观结构和性能突然变化而存在缺陷。激光金属沉积（LMD）-电弧增材制造（WAAM）工艺可以通过沉积功能梯度材料（FGM）层来减轻两种不同材料之间的缺陷，例如使用LMD沉积薄中间层，并可用于以相对较低的成本通过WAAM以高沉积速率制造双金属结构。在本研究中，进行了LMD-WAAM工艺，并研究了制造的IN625-SUS304L双金属结构的微观结构。LMD-WAAM样品的FGM区的微观结构主要是细小等轴枝晶形态。相比之下，粗大的柱状枝晶形态构成了WAAM区。LMD-WAAM样品的主要合金元素组成随沉积层高度逐渐变化。LMD-WAAM样品的显微硬度倾向于随着因科镍合金含量的增加而增加。在LMD-WAAM样品中，断裂发生在25% IN625和0% IN625之间的界面附近；在WAAM样品中，最终断裂发生在靠近界面的SUS304L中。LMD-WAAM样品的拉伸强度与激光功率成反比。结果表明，LMD-WAAM样品的拉伸强度比仅使用WAAM制造的样品高8%。
