Development of High Temperature Al-Ce-Mg Alloys—Thermal Stability and Mechanical Properties

A new generation of temperature resistant Al alloys based on the Al-Ce-Mg system is required for applications in supersonic aircraft fuselage design. This will replace some of the components currently made from Ti with much lighter Al, with subsequent weight savings in both structural and thrust producing aircraft components. The aim is to overcome the present barriers and to develop novel aluminium alloys with superior properties that are stable across the temperature required for aerospace applications. Al alloys are resistant to exposure to elevated temperatures by adding Ce. Ce has low diffusivity in Al, which prevents precipitate coarsening and ensures microstructural stability. It is possible to further improve the strength of as cast binary Al-Ce alloys by alloying with Mg, providing solid-solution or precipitation strengthening.<br/>The cast Al-10Ce-4Mg binary alloy was produced with slab casting and further processed by rolling and extrusion. The mechanical properties and microstructural characterization were carried out on as cast, rolled, and extruded conditions. The as cast, rolled, extruded Al-10Ce-4Mg was used to evaluate property retention after exposure to elevated temperature for various durations and testing at different temperatures. Extruded Al-10Ce-4Mg alloy showed better thermal stability than available high temperature Al alloys like Al-2618. The microstructures generally involve the Al₁₁Ce₃ intermetallic phase within the Al-Mg solid solution. To achieve high strength, a uniform dispersion of fine intermetallic is desirable. This work provides a new idea for developing heat-resistant aluminum alloys with a good combination of strength and ductility via thermomechanical processing like rolling and extrusion.