Preparation of Cu-TiN alloy by external nitridation in combination with mechanical alloying

A copper alloy dispersion strengthened by TiN was prepared by external nitridation in combination with mechanical alloying. After mechanical alloying pure Cu and Ti powders, a Cu-3wt.%Ti solid solution was formed. These powders were nitrided at 1073 K, resulting in a TiN layer on the surface of the copper powders. Further mechanical alloying was very efficient in breaking down the TiN surface layers. A very fine uniform distribution of nanosized TiN was obtained. The resulting copper alloy had a grain size of about 150 nm in diameter after annealing at 1173 K in vacuum for 5.4 ks, and showed a very high room temperature hardness value of 251 kg mm−2 which was independent of annealing temperature below 1173 K.