The crystallographic texture and dependent mechanical properties of the CrCoNi medium-entropy alloy by laser remelting strategy

Abstract

• The <111> crystallographic orientation in the scanning direction was first found in this study. • The evolution mechanism of texture under different laser remelting scanning strategies is systematically analyzed. • The reasons for the difference in mechanical properties under different laser remelting scanning strategies have been studied. • The microstructure evolution and fracture morphology of the sample after tensile are discussed. Laser remelting (LR) has attracted widespread attention in recent years as an effective method to reduce internal defects and improve the surface quality of additively manufactured (AM) parts. In the present study, three different LR inter-layer scanning strategies (LR0, LR90 and LR45) and their effects on the porosity, microstructure, crystallographic texture and related mechanical properties of parts have been studied. Optical microscope, X-ray diffraction, and scanning electron microscope were used as characterization tools. In the LR90 sample, it shows obvious {111} <110> texture and strong <111> preferred orientation along the scanning direction (SD), while the 0° offset and the 45° rotation of LR scanning strategy form a finer microstructure and weak crystallographic texture. Meanwhile, the mechanical properties of the LR sample are improved compared with the sample only by laser metal deposition (LMD), and a combination of higher strength and optimal uniform elongation is obtained in the LR45 sample. The overall results show that a reasonable LR scanning strategy can reduce the anisotropy of AM parts and improve their mechanical properties.