Aluminum Pistons Bowl Rim Reinforcement with Ceramic Fibers and Rapidly Solidified Alloys

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.