Design of Interfaces in Metal Matrix Composites.

摘要

The main goal of this research was to optimize the interface properties in metal matrix composites by lattice matching the matrix and the dispersoids. Stable, coherent dispersoids can be achieved by mechanically alloying lattice-matched dispersoids into metal matrices and allowing some recrystallization or coarsening to occur, or by internal nitridization or carburization of homogeneous alloys. A model system that has a high probability of forming coherent interfaces is ZrN in Nb. For comparison purposed the relatively poorly matched systems TiN in Nb and TiN in Cu were also studies. The matrix/dispersoid orientation relationship in the Nb/ZrN system has been found to be (011)Nb,Zr (parallel) (001)ZrN. In the Nb/TiN system, the presence of an orientation relationship after extensive nitriding could not be detected. In the Cu/TiN system only external nitridation occurred when bulk Cu-Ti alloys were employed. However uniformly distributed nanosized TiN dispersoids were obtained when alloyed Cu-Ti powders were nitrided and subsequently mechanically alloyed.