Characteristics of heat resistant nanoquasicrystalline PM aluminum materials

This article reviews the development of a series of high performance powder metallurgy (PM) aluminum materials. The materials are reinforced with large volumes of nano-sized quasicrystalline spherical particles evenly dispersed in the aluminum matrix. Typical size of the nanospheres is 20-300 nm. The core of the spheres appears to be crystal (cuboids) while the rest of the spheres are largely amorphous. The unique microstructures lead to significant improvements in the microstructural thermal stability and mechanical property of the materials. Ultimate tensile strength of the alloy remains almost unchanged after having been annealed at 400°C for an extended period. The fatigue strength of the alloy is also increased to a level comparable to sintered steels. The enhanced properties of the alloys could allow the materials to be used for medium to high stress applications including those subjected to cyclic stresses at elevated temperatures.