Metal matrix composites reinforced by gas-atomised Al-Cu-Fe powders

An Al62Cu26Fe12 alloy was gas-atomised to prepare powders containing icosahedral quasicrystalline phase. For synthesizing composites, pure Al was selected as matrix material, and the Al62Cu26Fe12 powders were added to the molten aluminum during the casting. A Ni coating with a thickness of approximately 5 μm deposited onto the Al62Cu26Fe12 particles proved to be effective in preserving the original powder structure during casting. The composites showed a relatively good bonding between the Al62Cu26Fe12 particles and matrix, despite the partial dissolution of the small satellite particles. Mechanical properties evaluated through compression and indentation tests of the composites indicated a significant increase of the yield stress especially in the range up to 10% volume fraction of reinforcing particles. Strengthening mechanisms were reviewed to estimate the role of the icosahedral and coexisting crystalline phases on the increase of the yield stress.