Effects of laser cladding of silicon carbides particles and iron based powder

The objective of this study was to develop clad layer by producing a Silicon Carbide (SiC) particle reinforced Metal Matrix Composite (MMC) using the iron based alloys (P25) as the matrix material. Direct laser cladding was carried out by melting the clad materials and depositing them onto a mild steel substrate. A two gravity feed system was used in this study which contained of SiC particles and iron based powder as separate powders. The intention was to melt the iron based powder and incorporate the SiC particles. Decomposition of SiC particles was observed and only a few SiC particles were found in the clad matrix. Microhardness results showed that laser clad layer had higher hardness which more than 1000 HV and hence potentially better wear resistance that base material. However, most of the SiC had evaporated which created porosity in the melt pool due to the decomposition of SiC and the resultant gas which was trapped in clad layer did not have enough time to escape from the melt pool due to the rapid solidification. Therefore, a blown powder technique is recommended for overcome this problem.