A strong, ductility maintained, and high-temperature resistant Ti-based composite with TiC@(TiCr2+α-Ti) reinforced particles

Abstract

While material with light, strong, and high-temperature environment resistant is highly attractive to aeroengines, achieving the combination of all these properties in composite remains a challenge. As these properties typically require the combination of various materials, especially incorporating the extremely brittle intermetallic compound at room temperature into a particle-reinforced composite inherently troubled by the "strength-ductility" contradiction, which can easily exacerbate the inherent brittleness of the material. Herein, we present a composite based on Cr2AlC-Ti system, which generates reinforcements with TiC@(TiCr2+α-Ti) shell-core architecture in the Ti matrix through a straightforward eutectoid reaction. The reinforcements are continuously distributed on a macroscopic level, establishing a co-continuous structure with β-Ti in 3D space. Microscopically, the shell-core structure has a multi-level TiCr2/α-Ti alternating layer structure as in natural nacre. This multi-scale and multi-level structural design overcomes the brittleness of TiCr2 at room temperature by controlling its morphology and distribution, and achieves high content of ceramic particles in composite. The resulting composite has a compressive strength of about 2GPa at room temperature, and even at 600 °C when Ti matrix is completely softened, the composite has a commendable strength of about 800MPa.