Improved wear behaviour of alumina-aluminium titanate laminates with low residual stresses and large grained interfaces

The wear behaviour of a monolithic alumina and an alumina-aluminium titanate laminated structure was studied. The laminate, containing surface fine grained alumina layers and internal composite layers with 10 vol.% of aluminium titanate, showed relatively low (~= 20MPa) compressive residual stresses at the surface. Interfaces between layers were constituted by large alumina grains (up to ~= 50um) that promoted toughening due to crack deflection and branching. Wear tests were performed on square specimens (30mm×30mm×6 mm) using the pin-on-disc method. The laminates showed higher wear resistance than the monolithic alumina. The analysis of the results together with SEM-EDX observations was performed to identify possible wear mechanisms. The wear resistance improvements are discussed in terms of the residual stresses in the laminate and the properties provided by the special microstructure of the interfaces