The influence of NH3 plasma treatment on microstructure and mechanical property of AlSi10Mg alloy fabricated by selective laser melting

In this work, we report an innovative route to modify atomized spherical AlSi10Mg powder by NH3 plasma treatment and further investigate their influences on the microstructure, mechanical and wear properties of AlSi10Mg alloy fabricated by SLM technology. The results indicated that the SLM-PT AlSi10Mg alloy exhibited a better mechanical and wear performance in comparison with the SLM-Atomized AlSi10Mg alloy, the hardness, ultimate tensile strength and elongation increased from 126.2 HV to 131.3 HV, from 350 MPa to 400 MPa and from 3.0% to 5.5%, respectively. The improvement of mechanical properties was stemmed from a combination of N radical adsorbed on the surface of the raw Al powder through NH3 plasma treatment and in-situ AlN nanocrystallites in the advancing liquid phase during SLM processing. High wettability in the Al-AlN promotes to wetting and spreading of molten aluminum against in-situ AlN surfaces, thereby favouring pore filling during SLM process. Thus, SLM-PT AlSi10Mg alloy exhibits a higher density and a better metallurgical bonding of Al/Al and Al/Al-Si eutectic than that of SLM-Atomized AlSi10Mg alloy.