Microstructural evolution of AISI 4340 steel during Direct Metal Deposition process

▶ 4340 steel was successfully deposited using diode laser DMD system on mild steel. ▶ Ferrite, martensite and cementite microstructural phases were identified in the clad. ▶ Lattice parameters of identified phases are shorter than reported lattice parameters. ▶ Microhardness of the clad decreases down the clad layers. ▶ Decrease in microhardness corresponds to degree of tempering of martensite phase.