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 form ed. These powders were nitrided at 1073 K, resulting in a TiN layer on the surface of the copper powders. Further mechanical alloying was ve ry efficient in breaking down the TiN surface layers. A very fine unif orm distribution of nanosized TiN was obtained. The resulting copper a lloy had a grain size of about 150 nm in diameter after annealing at 1 173 K in vacuum for 5.4 ks, and showed a very high room temperature ha rdness value of 251 kg mm(-2) which was independent of annealing tempe rature below 1173 K.