Composite alloy for IC engine pistons

Aluminum is the most popular matrix for the metal matrix composites The Al alloys are attractive due to their low density, their capability to be strengthened by precipitation, their good corrosion resistance, high thermal and electrical conductivity, and their high damping capacity. The characteristics of metal matrix composite materials are determined by their microstructure and internal interfaces, which are affected by their production and thermal mechanical treatment. Investigations to improve the combustion piston engines are leading to improve the working process performance by increase of its parameters, especially the average temperature of the thermodynamic cycle. New piston consists of two parts manufactured of standard and composite materials are presented in the paper. Composite alloy has chemical composition of short fibre with Al2O3 was following, in the mass percentage: 96% Al2O3, 4% SiO2. As the binder the colloidal silica was used in quantity 5%. The volume of fibres in the insert was 22±2% by volume. Bending strength of the insert was 0.5 MPa. Temperature and stresses distribution in standard piston and different versions of composite pistons are introduced in the paper. The paper presents the resistance of investigated materials on thermal shocks. Experimental verification of manufactured composite pistons in the engine proved the larger exhaust temperature for about 20-70°C, in comparison with the engine with standard pistons (that gives the greater effectiveness of turbo charging application), proved the lowering of a individual volume of gases blow-bys to the crankcase, the lowering of noise level, larger resistance on thermal loads