Mechanism of abrasive wear of Al-Si hypoeutectic alloycontaining 5 vol% fly ash

Abstract

Fly ash, an inexpensive resource material, has been introducedinto Al-Si hypoeutectic alloy (A356) to make low-cost compositeswith decreased density and improved hardness and abrasive wearbehavior. The mechanisms of abrasive wear of stir-cast A356-5vol% fly ash composite were discussed based on the results ofwear tests of composites and the A356 base alloy. Scanningelectron microscopy was used to investigate the morphology ofthe worn surfaces, wear debris for both composite and A356 basealloy. The subsurface of the worn samples was also observed.These morphology observations provide a method to understand theabrasive wear and friction mechanism of the composites showing that the base alloy wears primarily by microcutting but thecomposite wears by microcutting and delamination caused by crackpropagation below the rubbing surface through interfaces of flyash and silicon particles with the matrix.