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This paper discusses a joint customer-supplier program intended to further develop the ability to design and apply aluminum alloy pistons selectively reinforced with ceramic fibers for heavy duty diesel engines. The approach begins with a comprehensive mechanical properties evaluation of base and reinforced material. The results demonstrated significant fatigue strength improvement due to fiber reinforcement, specially at temperatures greater than 300°C. A simplified numerical analysis is performed to predict the temperature and fatigue factor values at the combustion bowl area for conventional and reinforced aluminum piston designs for a 6.6 liter engine. It concludes that reinforced piston have a life expectation longer than conventional aluminum piston. Structural engine tests under severe conditions of specific power and peak cylinder pressure were used to confirm the results of the cyclic properties evaluation and numerical analysis.

Squeeze casting is, nowadays, the more widely accepted industrial process to produce Aluminum Alloy heavy duty pistons reinforced with short ceramic fibers (FRM). However, rapidly solidified aluminum alloys (RSA) have not yet received much attention as an alternative material for local piston reinforcement, although they have far more strength than the fiber preforms, the starting raw material to produce FRM. The aim of this paper is to show the production routes to manufacture bowl rim reinforced pistons with FRM and RSA, followed by the analysis of some criteria affecting the mechanical properties of FRM (related to the fiber geometry and their chemical reaction with the metal matrix) and of RSA (powder metallurgy versus spray deposition). The resulting macro-interface is also considered as a discontinuity of properties. Finally, some engine test results obtained with pistons reinforced with FRM and RSA are compared with the results obtained on baseline Aluminum Alloy pistons.