EFFECT OF PROCESSING PARAMETERS ON THE CHARACTERISTICS OF AI/SiC NAN000MIPOSITE P0WDIERS PRODUCR)D) VIA IN SJTU |POW)}}|R METALLURGY METHOD

In the present investigation, the effect of different processing parameters on the characteristics of Al/SiC nanocomposite powders produced via in situ powder metallurgy (IPM) method is investigated. Specified amounts of micron sized SiC particles (SiC in two size ranges of 300-600 and 500-800 m) together with SiC nano-particles (SiC with the average size of 60 nm) were preheated and added to Al-2.5 wt.% Mg melt. This mixture was stirred via an impeller at 750 °C for 6 min. The kinetic energy of the impeller was transferred to the melt via the non-wetting SiC particles and resulted in melt disintegration. The liquid droplets created by this process were then solidified upon cooling the blend resulting in a mixture of Al powders and SiC particles. This blend was passed through a sieve to remove SiC.m. particles. The resultant mixture of Al powders and SiC. particles was ready to be used as a feedstock for preparation of nanocomposites. Effect of the stirring speed, SiC/Al weight ratio, size of SiC particles and the wt.% of the used SiC on the size of the produced powders and the yield of process were investigated. It was concluded that an increase in the surface of atomizing particles reduces the size of Al powders. However, there is an optimum value for stirring speed corresponding to a minimum in the mean Al powder size. Microstructural studies revealed successful embedding of SiC in the Al powders.

Keywords:

Al/SiC nanocomposite powders , in situ powder metallurgy , laser particle size analyzer