Microstructure and properties of extruded rapidly solidified AlCr4.7Fe1.1Si0.3 (at.%) alloys

The rapidly solidified AlCr4.7Fe1.1Si0.3 (at.%) alloy produced at large scale by direct extrusion of gas atomised powders was investigated. Hot-extrusion yielded sound compacts and did not create any major structural changes compared to the as-atomised state. Microstructural characterisation of the as-extruded material revealed submicron scale α-Al grains with an embedded Al7Cr crystalline phase and traces of a nano-scale quasicrystalline Al84.6Cr15.4 phase. The long-term thermal stability up to 300 °C of compacts was proven. The thermal stability of compacts was accompanied by high mechanical properties, especially high strength and Young's modulus, and creep performance up to 300 °C. The same material was prepared by laboratory scale extrusion of cryo-chopped melt-spun ribbons as a reference material. No major differences in the structure or properties of the industrially prepared material were observed compared to the reference material.

► Gas atomised AlCr4.7Fe1.1Si0.3 powder hot extruded at large scale. ► Exceptional thermal stability and high strength of compacts up to 300 °C. ► High Young modulus, low CTE and good creep performance of compacts. ► No major differences compared to the reference melt-spun ribbons based material. ► Technologically feasible manufacturing at large scale.