The Emergence for Multilamellar Ti–Al–N Solid Solution in Ti/AlN Composites Sintered at Various Temperatures

Nowadays, a variety of coatings such as Ti–Al–N and TiN have been proposed in titanium machining, but few results on fabrication of bulk Ti/AlN composites were reported. Here, we prepared bulk Ti-60 wt%AlN composites via vacuum hot-press sintering at 1250°C–1450°C under an applied pressure of 30 MPa for 1 h. With sintering temperature increasing, the mechanical properties of Ti/AlN composites improved and achieved the maximum values when the sintering temperature is 1450°C. SEM detected the multilamellar grains which are confirmed as Ti–Al–N solid solution by XRD and EDS. Finally, microstructure evolution and phase transformation of Ti/AlN composites were illustrated that Al and N atoms diffuse across the grain boundary and react with Ti atoms to form TiN phase and multilamellar Ti–Al–N solid solution. This work is interesting for producing high strength and toughens metal/ceramic composites.