Abstract
The in-situ formation mechanism of nano-scale AlN particles on the surface of pure Al powder by direct nitridation and mechanical properties of resultant P/M Al-AlN composite were investigated. Nano-scale AlN particles were formed on the powder surface by heat treatment at 873 K in N_2-H_2 mixed gas. The mean particle size of AlN was estimated as about 40-80 nm by TEM observation. Yield strength (YS) and ultimate tensile strength (UTS) of P/M extruded Al-AlN composites powder increased with increasing AlN content. On the other hand, the elongation of Al-AlN composites slightly decreased. Increment of UTS of P/M extruded Al-AlN materials was larger compared to that of YS, suggesting that the work hardening of Al-AlN composite was improved by AlN dispersion strengthening.
