Metal Additive Manufacturing Conference - MAMC 2023

Microstructures of single layer AISI M4 high speed steel deposited on AISI D2 tool steel substrate using L-DED process with two levels of global energy density were characterized and compared.
A five-axes PRECO-SL 8600 CNC machine was used to deposit the M4 powder feedstock with a continuous wave laser source, near-infrared wavelength laser beam, 2.0 mm spot size and coaxial continuous feed nozzle. The M4 powder had particle size between 60 μm and 210 μm and volumetric mean diameter of 119µm. The quenched and tempered D2 substrate was 15 mm thick with 755 HV hardness. Two laser power/scan speed sets were used: 700 W/800 mm/min and 1100 W/500 mm/min, that is GED = 26.3 J/mm2 and GED = 66 J/mm2, respectively.
The microstructures were characterized through optical micrography, SEM, EDS microanalysis and EBSD.
Four different zones could be distinguished, owing to their microstructure features: deposition, dilution, HAZ and substrate. The effect of GED on the microstructure features was explored.