Study on interface and mechanical properties of Ti–Al3Ti metal-intermetallic laminate reinforced by Ni-plated woven carbon fibers

Abstract

Ni plated continuous woven carbon fibers (Ni–Cf) reinforced Ti–Al3Ti metal-intermetallic laminate composites (Ni-CfR-MIL) were prepared by electroplating assisted hot pressing sintering (HP). Scanning electron microscopy (SEM) was used to characterize the effect of Ni plating on the Cf surface, structure and interface of the composites. The diffusion distribution of elements was observed by using electron probe microscope analyser (EPMA) and energy dispersive spectrometer (EDS). Transmission electron microscopy (TEM) was used to observe and calibrate the interface in nanometer scale. The experimental results show that the interior of Cf bundle is completely infiltrated by Al. The Ni plating can promote the infiltration between Al and Cf, inhibit the interface reaction between Al and C, reduce the formation of harmful phase Al4C3 at the interface, and improve the bonding strength of Cf and matrix. There are diffusion layer I(Al3Ti) and diffusion layer II(Al13Fe4 & Al3Ni) in the material. Al4C3, Al13Fe4 and Al3Ni phases are formed by interfacial reaction during HP, and diffusion phase Al3Ni is precipitated in the Al3Ti layer near Ti layer. The tensile strength of Ni-CfR-MIL is 596Mpa and the fracture strain is 8.94%, both of which are better than that of Ti–Al3Ti MIL without fiber. The bending strength of Ni-CfR-MIL reaches 1101Mpa and the failure strain is 2.33%, which are 3.2 times and 1.9 times that of Ti–Al3Ti MIL respectively. By observing the crack of the failure fracture, the cause of performance improvement was analyzed.