Effects of Process Parameters on Forming Quality and Microstructure of FeCrAl-ODS Alloy Fabricated by Selective Laser Melting

TL;DR

This study explores how laser settings affect the quality and microstructure of a FeCrAl-ODS alloy made using 3D printing.

Contribution

The study identifies optimal laser parameters that minimize defects and improve hardness in FeCrAl-ODS alloys via SLM.

Findings

Hatch spacing of 0.06 mm minimized cracks and pores in the alloy.

Excessive laser power or energy density caused grain coarsening and reduced hardness.

Optimal parameters produced fine grains, high hardness (293 HV), and significant residual stress.

Abstract

This study systematically investigated the effects of selective laser melting (SLM) process parameters on the forming quality and microstructure of FeCrAl oxide dispersion-strengthened (ODS) alloy. Through orthogonal experimental design, the influences of laser power (300–320 W), scanning speed (650–850 mm/s), and hatch spacing (0.05–0.07 mm) on the surface morphology and internal defects of as-built samples were analyzed. The microstructural evolution under different volumetric energy densities (VED) was also analyzed. The results indicate that hatch spacing significantly affected crack and pore formation, with minimal defects observed at 0.06 mm. Excessive laser power (320 W) or VED (318.0 J/mm3) led to elevated melt pool temperatures, causing element evaporation, grain coarsening, and <100> preferential oriented texture, thereby reducing hardness to 234 HV. The optimal parameters—laser power of 310 W, scanning speed of 650 mm/s, and hatch spacing of 0.06 mm (VED 265.0 J/mm3)—yielded the highest hardness (293 HV), fine-grained structures, and a high proportion of low-angle grain boundaries (LAGBs) with significant residual stress. This research provides a theoretical foundation for optimizing SLM processes for FeCrAl-ODS alloys.

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