Demographic Changes by the Vickers Microhardness Surface Indentations on the TiC Metal Matrix Composite TIG Melted Track

Vickers microhardness testing is considered as the most suitable way to measure hardenability of metallic or semi metallic material because the method is low of operational cost, adaptive to skill or semi skill operators with variety of available testing load either to determine specific microstructure at grain sizes or an area having variety of microstructural features. The objective of the study is to determine the demographic changes of the fabricated TiC metal matrix composite TIG layer under the influence of Vickers microhardness indentation at 500 gf. In this work the TiC metal matrix composite layer was produced on the surface of AISI 4340 low alloy steel layer via TIG arc source. While the microhardness values were obtained by measuring the diagonals using attached optical apparatus to the testing machine, scanning electron microscope was used to determine the demographic changes caused by permanent diamond impression. The results showed that protuberances were obvious in the heat affected zone and the substrate due to material dislocation as the metal being pressed over their elasticity limit by the side of the indentation. Populated carbides were the reasons to resist such high dislocation followed by evident from absence of protuberances giving near to 1000 HV than the heat affected zone and substrate at 570 HV and 300 HV respectively.