Abstract:Bulk intermetallic-ceramic composite Al2O3/Ti4AlN3 was fabricated by in-situ hot isostatic pressing of Al3Ti/TiN nanopowders under 1280 ℃/150 MPa/1 h conditions . The microstructure of composite were investigated by X-ray diffraction, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope). It is revealed that matrix Ti4AlN3 grains are strip-like and Al2O3 particles disperse in matrix uniformly with irregular shape. The averagegrain size of Ti4AlN3 is 7 μm. The size of Al2O3 particles are in the range of 1-3 μm, and volume fraction is about 40%. The Vickers hardness of Al2O3/Ti4AlN3 composite is 6.7GPa, maximal compressed strength is 1 800 MPa. Maximum compressive strain increased from 4% to 6.2%.Compared with the micro-hardness and compressed strength，Al2O3/Ti4AlN3 composite is higher than single Ti4AlN3 phase. The strengthening mechanisms of composite are fine grain strengthening and second phase strengthening.