Zhang Yanqiu, Jiang Shuyong
College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China.
Materials (Basel). 2018 Oct 12;11(10):1957. doi: 10.3390/ma11101957.
Based on molecular dynamics (MD) simulation, the behaviors and mechanisms of diffusion welding between 304 stainless steel (304 SS) and pure Ni were investigated in the present study. The results show that surface roughness has a significant influence on the diffusion behaviors of atoms during diffusion welding between two different materials, and it is suggested that the rough surface should be set on the pure Ni rather than the 304 SS during the diffusion welding between them. Temperature plays an important role in the interface diffusion. With the increase of temperature, the number of atoms diffusing into the opposite side increases and the diffusion distances increase as well. As a consequence, the diffusion welding should be performed at a suitably elevated temperature. The influence of vertical pressure on the diffusion bonding between the two materials includes two aspects. One is to increase the contact area via deforming the asperities or grooves at the interface, which provides more opportunities for the diffusion between the two materials. The other is to reduce the mobility of atoms within a lattice. As a consequence, the pressure effect is smaller than temperature effect during diffusion welding between 304 SS and pure Ni.
基于分子动力学（MD）模拟，本研究对304不锈钢（304 SS）与纯镍之间的扩散焊接行为及机理进行了研究。结果表明，表面粗糙度对两种不同材料扩散焊接过程中原子的扩散行为有显著影响，建议在它们之间进行扩散焊接时，粗糙表面应设置在纯镍上而非304 SS上。温度在界面扩散中起重要作用。随着温度升高，扩散到另一侧的原子数量增加，扩散距离也增加。因此，扩散焊接应在适当提高的温度下进行。垂直压力对两种材料之间扩散结合的影响包括两个方面。一是通过使界面处的凸起或凹槽变形来增加接触面积，这为两种材料之间的扩散提供了更多机会。另一个是降低晶格内原子的迁移率。因此，在304 SS与纯镍之间的扩散焊接过程中，压力效应小于温度效应。
