A Novel Chemical Process for Production of Aluminum Alloy Composites

Aluminum alloy composites with AlN particulates were successfully formed in situ (a novel chemical synthesis process) by injecting ammonia precursor gas. Experimental yield of AlN in alloy (Al-7 wt % Si) was found to increase with increased injection time or increased flow rate. The optimized conditions for producing uniformly dispersed AlN composites in laboratory scale are ammonia flow rate in the range 3.3 - 5E-06 m³/s, injection time of 90 minutes and temperature of 1273 K. AlN particulates formed are small in size (<1 mm). The AlN yield was found to increase on increasing either bubbling time and or flow rate. Vickers micro hardness of the composite measured were found to increase linearly with the nitride content in the composite. With the advantage of using economical precursor gas, this in situ gas injection process is an emerging cost-effective production process for the DRACs.