A high strength low alloy steel fabricated by direct laser deposition

Abstract

Direct laser metal deposition (DLMD) can produce near net shape parts by layer-by-layer deposition of metallic powders. In the present study, DLMD was used to fabricate a high strength low alloy (HSLA) steel. The characteristics of the microstructure and mechanical properties of the as-built HSLA were characterized using optical microscopy, electron back-scatter diffraction (EBSD), transmission electron microscopy, and tensile test machine respectively. It was found that the optimized parameters ensured a high quality of the built samples. The as-built HSLA steel was mainly composed of α-Fe (Ferrite) phase with a trace of C6Cr23 and Fe3C phases. TEM result proved the formation of martensite phase. Most grain boundaries misorientation angles were low-angle grain boundary which elevated the strengthening effect. Tensile strength, yield strength, and elongation of the as-deposited HSLA were comparable with other high-performance alloy steels. The present results show the potential of DLMD for the fabrication of a HSLA with excellent mechanical properties.