We Energies Coal Combustion Products ... - The White House

Chapter 8
Fly Ash Metal Matrix Composites
Introduction
Metal matrix composites (MMCs) are engineered materials formed by the
combination of two or more materials, at least one of which is a metal, to
obtain enhanced properties. MMCs tend to have higher strength/density and
stiffness density ratios, compared to monolithic metals. They also tend to
perform better at higher temperatures, compared to polymer matrix
composites.
Though MMCs have been in existence since the 1960s, their commercial
applications have been limited due to their higher cost and lack of proper
understanding. More recently developed MMCs, especially cast aluminum-fly
ash composites, have the potential of being cost effective, ultra light
composites, with significant applications (56). Such composites, if properly
developed, can be applied for use in automotive components, machine parts
and related industries.
Figure 8-1: Brake drum cast with aluminum ash
alloy material in Manitowoc, Wisconsin
Aluminum and magnesium are
lightweight materials, when
compared to iron and steel.
However, they do not have the
strength requirements necessary
for several applications. Metal
matrix composites manufactured
by dispersing coal fly ash in
common aluminum alloys improve
mechanical properties
such as hardness and abrasion
resistance.
Processed fly ash is estimated to
cost about $0.10 per pound
(including the cost of mixing the
ash into the aluminum melt).
Aluminum alloy 380 costs
193 We Energies
Coal Combustion Products
Utilization Handbook