A Novel Method to Make Tough Ti_2AlC/Al_2O_3- and Ti_3AlC_2/Al_2O_3-Laminated Composites

摘要

A novel method to fabricate titanium aluminum carbides/ alumina-laminated composites with weak interfaces was developed through heat treatment titanium aluminum carbides at 1300℃ and low oxygen partial pressure. The laminated composites consist of 0.5-mm-thick layers of titanium aluminum carbides joined together by the in situ formed A1_2O_3 interlayers. The interfaces are free of cracks or delaminations. These laminated materials exhibit better damage tolerance compared with the monolithic counterparts. Crack deflection along the Al_2O_3 interlayers was the main mechanism for the noncatastrophic failure. The fracture toughness was increased from 4.9 MPa·m~(1/2) for Ti_2AlC to 7.3 MPa·m~(1/2) for Ti_2AlC/Al_2O_3 composite and from 6.5 MPa·m~(1/2) for Ti_3AlC_2 to 10.4 MPa·m~(1/2) for Ti_3AlC_2/Al_2O_3 composite, and the work of fracture required to break samples was increased from 153 J/m~2 for Ti_2AlC to 676 J/m2 for Ti_2AlC/Al_2O_3 composite and from 300 J/m~2 for Ti_3AlC2 to 1317 J/m~2 for Ti_3AlC_2/Al_2O_3 composite.