High Temperature Tensile Behavior of A356-TiB2/TiC in-situ Composites

Abstract

In the present investigation, A356-TiB2/TiC composites with a various reinforcement ratios (0, 2.5, 5 and 7.5%) were synthesized through a K2TiF6-KBF4-Graphite (C) reaction system. Formation of TiB2 and TiC particulates and their distribution are confirmed by various characterization techniques. The tensile properties such as ultimate strength, yield strength, young’s modulus and percentage of elongation in addition to their failure behavior of were studied at ambiant and high temperatures (100, 200 and 3000C). The increment in the volume fraction of the composite raised the hardness and the enhancement of hardness was reported up to 49% at 7.5% reinforced composite due to the strengthening effect. The density and porosity of fabricated composites were investigated. The rise in the volume fraction of reinforcement phase decreased the density and increased the porosity of composite samples. Further, the ultimate strength, yield strength, young’s modulus declined with the rise in the temperature. Result analysis also illustrates that the 7.5% reinforced composite retained the ultimate strength up to 84.4% and the ductility was raised by 27% at 3000C. Yield strength and young’s modulus were also retained 74.31% and 71.09% respectively at the similar material and experimental conditions. The fracture surface analysis of the composites showed that, the ductile nature of failure appearance microscopically with the formation of fine dimples and voids on fracture surface at elevated temperatures. Cleavage facets and tear crumples observation indicated the brittle kind of failure at the ambient temperature. Findings from the experimental study provide the tensile behavior of the composites at the regular working temperature of the automobile engine piston.