Microstructure and mechanical properties of in-situ TiC hybrid reinforced TC4 matrix composites by a new additive manufacturing method

Abstract

As a new method to fabricate TiC-reinforced Ti matrix composites, pre-melted electron beam freeform fabrication was proposed based on in situ metallurgy using a graphite diversion nozzle. The feasibility of the method was investigated. Initially, the liquid TC4, an α+β Ti alloy, flowed into the graphite diversion nozzle, corresponding to the reaction between TC4 and graphite. Then, the fabrication of TiC occurred, achieving Ti matrix composites. The liquid TC4 was subsequently deposited on the TC4 substrate, indicating consolidated metallurgical bonding and the optimized hardness and abrasive resistance presented by the surface of the TC4 substrate. The deposited layer's microstructure and the TiC strengthening phase morphology in different areas were varied, considering the difference in the cooling rate and the flow mode. The distribution and morphology of the TiC strengthening phase in different regions were analyzed to reveal the underlying reasons for the property optimization of the TiC-TC4 deposited layer.

Keywords

• Additive manufacturing
• Metal matrix composites
• TiC
• Electron beam freeform fabrication
• Friction