Manufacturing of AA 2014 Matrix-B4C particulate composites and investigating properties

SUMMARY In this study metal matrix particulate reinforced composite was manufactured using AA2014 alumium alloy matrix and B4C particulate. Mechanical properties of manufactured composites such as hardness, tensile strength and elongation after fracture at different particul volume ratios were also investigated. It is very difficult to manufacture these composites because of bad wetting of liquid matrix of B4C particles. It is necessary to heat the liquid matris up to 1000°C in order to improve wetting properties. But this comparatively high temperature causes Excessive oxidation and gas entrapment in liquid metal. A new method was developped in this study which is based on cleaning of particule surfaces using an acid (% 50 HF +% 50 H2SO4) mixture before mixing with liquit alloy. B4C particles were dried at 150 °C for 12 -24 hours and preheated to 400 °C before adding to liquit alloy at 680°C. The results of microscopic examinations showed the particles were held inthe matrix and homogeneous mixture was obtained. Particle volume ratios were changed between % 1.5 to % 12 and the relations between particle volume ratios hardness and tensile strength and elongation after fracture were investigated. The test results showed that tensile strengths and elongations were decreasing with increasing particle content. This was attributed to ease of crack formation B4C/matris interfaces. Hardness test results indicated that hardness was increasing with particle volume ratio up to % 9. But it was decreasing again because of excessive porosity formation. Key words : Metal matrixcomposites, Particulate composites, Boron carbide, Vortex method, Mechanical properties