Evolution of microtexture and performance in TaC/316L composites fabricated by laser powder bed fusion

The laser powder bed fusion (LPBF) was used to fabricate 316 L stainless steel samples strengthened with 0, 0.5, 1.0, and 1.5 vol% tantalum carbide (TaC). The effects of the TaC content on the phase compositions, microstructures, impact toughness, and wear resistance of the TaC/316 L composites were investigated in detail. The microstructure and microtexture were regulated by the volume content of TaC. The 316 L grain size was refined from 695.9 mu m2 to 180.4 mu m2, and the maximum orientation density index decreased from 15.48 to 10.64 as the volume fraction of TaC was increase from 0 vol% to 1.5 vol%. Moreover, the X-ray diffraction (XRD) patterns of the samples showed that the diffraction peak of TaC in the composite powder gradually increased; however, this was not observed when the powder was processed by LPBF. The transmission electron microscopy (TEM) analysis indicated that the dislocation density significantly increased after the TaC content was increased. Moreover, after adjunction of TaC, the microhardness increased, and the friction coefficient and wear scar size decreased significantly compared to those of 316 L without TaC. The impact toughness decreased gradually with increasing TaC content, and the unstable fracture region increased sharply.