Cold sprayed WC reinforced maraging steel 300 composites: Microstructure characterization and mechanical properties

Maraging steel 300 (MS300) is a precipitation-strengthening iron-nickel alloy with outstanding properties such as good mechanical strength, weldability and corrosion resistance. However, the poor wear resistance has limited the application. In this work, high-performance WC reinforced MS300 composites were fabricated by high-pressure cold spray, which enables the additive manufacturing of bulk material well below its melting point. XRD analysis shows that no phase transformation occurred either to the WC reinforcements or the MS300 matrix. The distribution and morphology of the WC particles in the composite samples were characterized by X-ray computed tomography (XCT). The results show that a high retainability (85.4%) of WC particles was obtained at high working parameters (N-2, 5 MPa, 900 degrees C), and the solution-aging treatment resulted in decreased WC volume fraction and smoothing of WC shape. Microstructure observation of WC evolution shows that a thick diffusion layer was formed around the WC particle after solution-aging treatment significantly improving the interfacial bonding. Due to the more severe plastic deformation and higher WC retainability, the as-fabricated samples with higher propelling gas pressure demonstrate a higher tensile strength and better wear resistance. It is found that a higher solution temperature (1000 degrees C) can lead to an enhanced cohesive bonding within the composite. Finally, the solution-aged composite shows an excellent wear resistance under the improved WC bonding and precipitation hardening. (C) 2019 Elsevier B.V. All rights reserved.