Design and Preparation of Stepwise Functionally Graded Materials Used for Internal Combustion Engine Piston Applications


This work includes the design and preparation of a(Low carbon steel / AL2O3) stepwise functionally graded crown part of an internal combustion engine piston. Powder technology technique, has been studied to improve engine thermal efficiency by creating semi adiabatic combustion chambers, where ceramic phase facing the hot combustion gases, while metallic phase assembling with other parts of the piston. Finite element method ABAQUS program had been used to minimize nucleated residual stresses generated under fabrication process and service work conditions by designing the compositional graded of stepwise FGM within specific dimensions, in addition to temperature distribution across FGM thickness. Then the fabricated specimens had SEM imaging, physical and mechanical property inspection. The results also show that linear transition from metal to ceramic structure can provide minimum residual stresses under all conditions, using stepwise FGM can improve engine heat efficiency by doubling the crown surface temperature,(622) ºC, comparing with steel crown, (322) ºC, under the same applied heat flux. Physical inspections show limited relative density, (48.5) %, with high total porosity structure, (53.3) %, can be performed by this fabrication method. Mechanical tests results show that the layers’ hardness increase with increasing ceramic content, and decrease with increasing pores percentage. Compression test shows the ability of suggested stepwise FGM to withstand service work stresses of combustion chamber without failure.