Formation mechanism of interface layer of ZTA particle reinforced iron matrix composite

ZTA particle modified by Ti–Ni powder(Ti–Ni@ZTAp) reinforced iron matrix composite (Ti–Ni@ZTAp-VCp/Fe45) was fabricated by powder metallurgy. The microstructure, scratch properties and formation mechanism of the interface were investigated. An interface layer of 10 μm–20 μm was formed between ZTAp and VCp/Fe45 matrix, which reduced the defects at the interface and played a good transition role. The phases in the interface layer were TiO, Ti6O11 and ZrO2. Metallized layer was formed on the surface of ZTAp after the vacuum sintering of Ti–Ni powder modified ZTAp at 1500 °C. Elemental diffusion occurred between the Ti–Ni powder and ZTAp, which resulted that the ZrO2 phase migrated from ZTAp to the coating layer and reacted with the Ti–Ni powder to form new phases of Ni3Ti, TiO and Ti6O11. The models of the formation mechanisms of the metallized layer, interface layer between ZTAp and VCp/Fe45 matrix were established. Ni3Ti in the metallized layer on the surface of ZTAp was further decomposed duing the vacuum sintering of Ti–Ni@ZTAp-VCp/Fe45 composite, and then the elements Ni and Ti diffused with elements Fe, Cr and V of the VCp/Fe45 matrix. The V element diffusing to the interface layer can further displaced the Ti element in ZTAp and realized the diffusion from iron matrix to ZTAp. The metallized layer on the surface of ZTAp was transformed into an interface layer between ZTAp and VCp/Fe45.