激光成形修复Inconel 625合金的工艺特性和组织研究

Process Parameters and Microstructure of Laser Forming Repaired Inconel 625 Alloy

摘要:

对激光成形修复Inconel 625合金的工艺特性以及不同区域的组织进行了研究。结果表明：激光成形修复Inconel625 合金的工艺范围较宽；激光功率主要影响单道修复层的宽度；扫描速度对单道修复层的尺寸影响较为显著,而送粉率的影响较小。基材的相组成包括γ(Ni-Cr)基体相、大尺寸(约10μm)块状MC型碳化物(M为Nb和Ti)、沿晶界析出的小尺寸(约0.5 μm)块状MC型碳化物以及不规则形状的Laves相。修复区组织为呈外延生长的柱状枝晶,相组成为γ基体相、沿枝晶界析出的Laves相以及少量MC型碳化物。层与层界面处Laves相析出急剧增加形成层间过渡区。

Abstract:

The process parameters and microstructure of the laser forming repaired (LFR) samples of Inconel 625 alloy are investigated. The results show that a wide range of process parameters are suitable for the laser forming repairing of Inconel 625 alloy. The laser power mainly affects the width of single track LFR samples. The scanning velocity has significant effect on the size of single track LFR samples. The powder feeding rate has less effect on the size of single track LFR samples. The interface between the substrate and laser repaired zone (LRZ) shows a metallurgical bonding. The phases in substrate mainly consist of the γ(Ni-Cr) matrix, MC (NbC, TiC) carbids with bimodal sizes of about 10μm and 0.5μm, and laves phase. In the LRZ, columnar dendrites grow epitaxially from the substrate, approx following the deposition direction. The phases in LRZ mainly consist of γ matrix, laves phase and a small amount of MC carbids. Due to the increase of nucleation sites, a large ammount of laves phase are precipitated in the layer interface and track interface.