Abstract Laser cladding is a laser-based additive manufacturing (AM) process that is currently being used to coat part of a substrate or to produce a three-dimensional object in layer by layer following a computer-controlled instruction. In this study, laser-cladded AISI 420 martensitic stainless steel was characterized using the Electron Backscatter Diffraction (EBSD) technique to analyze the substructure of martensite in the selected zones such as the bead zone (BZ), the dilution zone (DZ), and the interface with the heat affected zone (HAZ) of the bead. The EBSD prior austenite grain (PAG) maps and inverse pole figure (IPF) revealed planer and columnar grains at the interface and within the adjacent dilution zone, while equiaxed and a combination of both columnar and equiaxed grains were observed in the center of the bead and dilution zone. The Grain Orientation Spread (GOS) and grain average Image Quality (IQ) techniques were used to quantify the grain misorientation and residual strain/stress in those selected zones. The EBSD analysis with the GOS and IQ values confirmed deformation and strain in the crystal lattice structure of those respective zones. The GOS approach revealed that most of the grains at the BZ and HAZ were highly strained and 26–59% fraction of the grains was at a high angle of GOS (3°–5°) indicating the availability of highly deformed grains in both regions. The IQ value was compared and correlated with the experimental values of residual stresses (RS) measured by XRD methods to understand residual strain distribution in those zones. It was revealed that the IQ value is inversely proportional to the RS value found in an earlier study. This EBSD parameter is expected to be used as an alternative method of analyzing RS distribution in the laser-cladded coating.

中文翻译：

---

激光熔覆 AISI 420 马氏体不锈钢的电子背散射衍射 (EBSD) 分析

摘要 激光熔覆是一种基于激光的增材制造 (AM) 工艺，目前用于涂覆部分基材或按照计算机控制指令逐层生产三维物体。在这项研究中，激光熔覆 AISI 420 马氏体不锈钢使用电子背散射衍射 (EBSD) 技术进行表征，以分析选定区域中马氏体的亚结构，例如焊道区 (BZ)、稀释区 (DZ) 和与焊珠热影响区 (HAZ) 的界面。EBSD 原始奥氏体晶粒 (PAG) 图和反极图 (IPF) 显示界面处和相邻稀释区内的平面和柱状晶粒，而在焊道中心观察到等轴和柱状和等轴晶粒的组合和稀释区。使用晶粒取向扩展 (GOS) 和晶粒平均图像质量 (IQ) 技术来量化那些选定区域中的晶粒取向错误和残余应变/应力。具有 GOS 和 IQ 值的 EBSD 分析证实了这些相应区域的晶格结构中的变形和应变。GOS 方法显示 BZ 和 HAZ 处的大部分晶粒高度应变，26-59% 的晶粒处于高 GOS 角度（3°-5°），表明这两个区域都存在高度变形的晶粒. IQ 值与通过 XRD 方法测量的残余应力 (RS) 的实验值进行比较和关联，以了解这些区域中的残余应变分布。结果表明，智商值与早期研究中发现的 RS 值成反比。