Crystallographic texture variation in laser beam-welded CoCrFeNiMn

Abstract

This study examines the crystallographic texture and residual stress variation of a laser-welded CoCrFeNiMn high-entropy alloy (HEA) plate. The HEA plate was welded using a disc laser with a maximum power output of 4 kW, which was also equipped with a bright line weld module and a dual-core fiber with a diameter of 100 and 400 μm, respectively. The welding direction was aligned with the rolling direction. The texture was investigated via high-energy X-ray beam and EBSD. To investigate the crystallographic variation in the welded CoCrFeNiMn HEA plate, the textures were examined in the fusion zone (FZ), the heat affected zone (HAZ), and the base material (BM). The texture observed in the FZ was a combination of the textures present on ±0.1 mm positions from the weld centerline. The texture identified on each side of the centerline of the FZ comprises fibers oriented 〈100〉 // to the transverse direction, exhibiting a ± 10° rotation around the rolling direction. The texture observed in the BM exhibits a rolling-type texture, represented by {110}<112> brass, {112}<111> Cu, and {123}<643> S components, with a dominant {110}<112> brass component and a sharpness of 4.8 mrd. The microhardness profiles indicate a slight decline in hardness, from 260 HV0.1 for the BM to 240 HV0.1 in the FZ. The mechanical properties of the welded samples exhibited a slight reduction in ultimate tensile strength (from 900 ± 15 MPa to 830 ± 10 MPa) and elongation (from 18 ± 3 % to 13 ± 3 %). This decrease in mechanical properties could be attributed to the presence of large grains in the FZ, the dissolution of precipitation, and alterations in texture. This alloy displays excellent weldability, making it a promising candidate for engineering applications.