The Preparation And Performance Of Mullite/Aluminium Titanate Laminated Ceramic Composites

The laminated ceramic composite,which is suggested by layered structure of natural shell,is a kind of the typical bionic structure material. As laminated structure is able to improve the fracture toughness and bending strength of the monolith ceramic, it had become a focus that material scientist pay attention to. In this paper, using mullite as the mitrix layer, and pure aluminum titanate (AT) and aluminum titanate/mullite composites (ATM) as the interface layer, the laminated ceramic composites with different sintering-process, different interface layer thickness and different component were prepared by using the roll-forming, tape-casting and hot-pressing. The influence of the sintering-process, the thickness and component of interface layer on mechanical properties and microstructure of mullite/aluminum titanate ceramic was studied, and the toughness mechanism also was analyzed. The study contents and result are showed:(1) The influence of hot-pressing temperature and pressure on the structure and mechanical properties of laminated ceramic composites were studied, the results showed that:With hot-pressing temperature increase, the flexural strength of laminated ceramic composites also gradually increase; When hot-pressing pressure is 20MPa,its fracture toughness and flexural strength all were up to maximum; Finally, The optimal sintering-temperature and hot-pressing pressure of mullite/aluminum titanate respectively was 1550℃and hot-pressing pressure was 20MPa;(2) The influence of interface layer thickness on structure and mechanical properties of laminated ceramic composites on studied,the results shows that:With the thickness of interface layer increase, the flexural strength of mullite/aluminum titanate laminated ceramic composites gradually decrease, and it's the fracture behavior gradually could change from linear elastic to the " Pseudoplastic "; (3) The influence of interface layer component on structure and mechanical properties of laminated ceramic composites on studied. In comparison of AT and pre-synthetic ATM, The anisotropy of bending strength could removed by using in-situ synthesis ATM as interface layer, using in-situ synthesis ATM as interface layer could remove the anisotropy of flexural strength,and flexural strength and fracture toughness would respectively be up to maximum, respectively to 189.82MPa and 3.98MPa-m1/2.In comparison with mullite monolith ceramic, the bending strength and fracture toughness respectively were up to 59.2% and 54.9%;(4) By analyzing path of the crack growth and displacement-load curves, we can obtain that toughening mechanism of mullite/aluminum titanate laminated ceramic composites was deflection and growth of main crack in interface layer.