Reinforcing effects of nano-WC in AlSi10Mg alloy assisted by in-situ surface modification approach

Abstract

A series of nano-WC surface modified AlSi10Mg powders with different WC contentswere synthesized by the electrostatic assembly method. After the selective laser melting (SLM) processing, various Al−W intermetallicswere in-situ formed in the SLM nano-WC/AlSi10Mg composites. A well-coherent Al/Al5W interface with a low lattice mismatch of 4.7% was confirmed with an orientation relationship of (002)α(Al)//(104)Al5W. The nano-WC particles and Al−W intermetallics triggeredthe columnar-to-equiaxed transition, leading to a fine equiaxed microstructure. As a result, the SLMed 3 wt.% nano-WC/AlSi10Mg composites showed remarkable mechanical properties, with an ultimate tensile strength of (464.1±8.68) MPa and elongation of (5.6±0.95)%. Additionally, the SLMed 3 wt.% WC/AlSi10Mg samples also achieved the lowest average coefficient of friction (0.429) and wear rate of 3.842×10−5 mm3/(N·m) compared to other WC/AlSi10Mg composites. The remarkable mechanical and wear properties are ascribed to fine-grain and second-phase strengthening.