Vacuum infiltration molding and mechanical property of short carbon fiber reinforced Ti-based metallic glass matrix composite

Abstract

• New vacuum infiltration method using Cu-mold-prepared CF preform is developed. • Electroless-Cu-plated layer dissolves to improve the wettability during infiltration. • Interface microstructure control is achieved by Cu-layer and short-term infiltration. • Ti-based CFRMGMC has obviously improved plasticity together with high-strength. • Randomly and uniformly distributed short CF leads to brittle-ductile transition. The molding process is the key technology for the development of carbon fiber reinforced metallic glass matrix composites (CFRMGMCs), which not only needs to tackle the challenge of the mixing uniformity of carbon fibers, but also should take into account the rapid cooling technology to obtain a fully glassy matrix. Herein, a new vacuum pressure infiltration molding method is developed to fabricate a Ti-based CFRMGMC, in which a copper mold is performed as the container for carbon fiber preforms in addition to being used as a rapid cooling device. In order to prevent the interface reaction between carbon fiber and metal liquid, an electroless copper layer is plated on the surface of carbon fiber. It is found that the thin copper layer is dissolved in the glassy matrix and no crystalline phase is formed on the interface between the fiber and the matrix, showing a good effect on the control of interface microstructure. Meanwhile, electroless copper layer also effectively improves the wettability between the carbon fiber and the titanium alloy melt, thereby improving the infiltration forming ability of the composite material and reducing the tendency to form macroscopic defects. The as-prepared Ti-based CFRMGMC shows a significantly improved plasticity of ∼5 % and a high yield strength of 1880 MPa. The toughening mechanism can be attributed to the random distribution of short carbon fibers in different directions, which originates from the preparing process of carbon fiber preforms. This multi-directional posture is frozen in the glassy matrix and stimulates the multiple shear band behavior of the CFRMGMC. This work sheds lights on the use of carbon fiber in bulk metallic glasses, and is of great significance to the lightweight development and the interface reaction control of CFRMGMCs.