Work

Powder-bed Fusion additive manufacturing of 316L stainless steel using short-wavelength diode point melting

Year: 2025

Type: article

Abstract: Diode Point Melting (DPM) is an alternative additive manufacturing powder-bed melting approach that combines multiple low-power, short-wavelength lasers into a single spot that is raster-scanned by an XY gantry to selectively melt deposited powder. In this study, the DPM laser head is composed of eight 450 nm diodes (∼35 W total) focused to ∼100 × 150 μm and is used to fabricate 316L stainless steel. Parts achieve >98% relative density while operating at slower scan speeds and estimated lower cooling rates than Laser Powder Bed Fusion (LPBF) (≈6.66×10 4 K s -1 vs ∼10 7 K s -1 ). The DPM microstructure is distinguished by larger grains (∼18 μm) and larger cellular sub-grains (∼2 μm) relative to the typical LPBF of 316L. It was demonstrated that cellular size decreases with increasing scan speed, evidencing cooling-rate control of the sub-grain structure. Mechanical characterisation shows a modest reduction in elastic modulus and Vickers hardness compared with LPBF-processed 316L, attributed to grain coarsening and slightly higher porosity, while values remain above those of conventionally manufactured 316L. These findings demonstrate potential for DPM to be a low-cost and accessible alternative to LPBF with unique microstructural characteristics.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2025.12.214

Authors: S. Can Erman, Alkim Aydin, Kamran Mumtaz

Institutions: University of Sheffield, Gazi University

Language: English

Topic: Additive Manufacturing Materials and Processes

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,640

Funder: Engineering and Physical Sciences Research Council