Microstructure characterization and properties of graphene oxide-reinforced tial matrix composites

Abstract

TiAl matrix composites reinforced with graphene oxide (GO) were prepared by powder metallurgy technology. The graphene oxide plates were added into TiAl powder by ultrasonic dispersion and milling, and then, shaped by Hot Isostatic Pressing (HIPing). Microstructures of the composites were characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) as well as Raman spectrum were conducted on the composite powder. The thermal and mechanical properties were tested on the TiAl matrix composites. The results show that the compression strength and heat conductivity of the composites can be improved distinctly at both room temperature and high temperature. The heat conductivity coefficient can reach to above 23 W/m K, and the compressive strength can reach to 1700 MPa at room temperature. GO was homogeneously dispersed into TiAl matrix in the form of random film with the diameter less than 10 µm. The minimum thickness of the GO film is about 5 nm. However, The GO does not well represent thermodynamically stable reinforcement at high temperatures, GO existed not only in the form of graphene but also a certain amount of Ti3AlC, and its size is about 2 µm rather than nanoscale, which can decrease the ductile reinforcement of GO in the TiAl matrix.