Effect of solid content on structure and properties of alumina ceramic matrix composite prepared by slurry infiltration method

Alumina fiber reinforced alumina ceramic matrix composites possess high temperature resistance, high strength and oxidation resistance, etc, and have a considerable application prospects in the field of thermal structural materials used in aerospace. Using NextelTM 610 fabric as the reinforcement, alumina ceramic matrix composites were prepared by Slurry Infiltration-molding process and sintered in a muffle furnace at high temperature for one time. The temperature range suitable for the preparation of composites was determined by the effects of heat treatment temperature on the crystalline phase, mechanical strength and other properties of fiber and matrix. The effects of solid content on the mechanical properties and microstructure of the composites were studied. The results show that the bending strength of NextelTM 610/Al2O3 ceramic matrix composite increases first and then decreases with the increase of solid content. When the solid content of the slurry is 60% (mass fraction,the same below), the bending strength is the largest, up to 370.68 MPa. When the solid content is less than 60%, the reason why the flexural strength of the composite is low is that the matrix in the fiber bundles is not filled enough. When the solid content increases to 65%, the degradation of the flexural strength of the composite is due to the formation of too many matrix defects and the strengthening of the fiber-matrix interface, which hinders the fiber debonding, pull-out and other toughening mechanisms.