Thermo-mechanical processing of high-performance Al-RE alloys
Production of a bulk Al-RE alloy body (product) using cast billets/ingots (cooling rates <100 C/s) or rapidly solidified Al-RE particulates (cooling rates 10 2 -10 6 ° C./second) that have beneficial microstructural refinements that are further refined by subsequent consolidation to produce a consolidated bulk alloy product having excellent mechanical properties over a wide temperature range such as up to and above 230° C.
1. A method of making a bulk Al-RE alloy body where RE is Ce, La, mischmetal, or any combination thereof, comprising:
a) solidifying a molten Al-RE alloy where RE=Ce, La, mischmetal, or any combination thereof, wherein the alloy has a composition consisting essentially of Al, RE, and at least one of Mg, Cu, Ni, Mn, and/or Zn to form an as-solidified Al-RE alloy with an Al-rich matrix, and
b) thermo-mechanical processing the as-solidified Al-RE alloy directly in an as-cast condition in a manner that refines at least a portion of a microstructural feature of the solidified Al-RE alloy, wherein the refined microstructural feature comprises at least one of reduced intermetallic phase size and reduced matrix grain size.
2. The method of claim 1 wherein the molten Al-RE alloy is solidified at a cooling rate less than 100 degrees C. per second as a cast billet, cast ingot, or other monolithic cast body.
3. The method of claim 2 wherein the cast billet, cast ingot, or monolithic cast body in the as-cast condition is directly subjected to thermo-mechanical processing.
4. The method of claim 1 wherein the molten Al-RE alloy is solidified by breaking up a molten stream of the alloy.
5. The method of claim 4 wherein the molten Al-RE alloy is solidified at a cooling rate of at least 10 2 ° C. per second and above.
6. The method of claim 1 wherein the molten Al-RE alloy is solidified in a mold.
7. The method of claim 6 wherein the mold comprises at least one of sand mold, permanent mold, and die casting mold.
8. The method of claim 1 wherein solidifying is by direct chill casting.
9. The method of claim 1 wherein thermo-mechanical processing of the as-solidified Al-Re alloy directly in the as-cast condition is conducted by at least one of extrusion, forging, sinter-forging, rolling, isostatic pressing, spray deposition, and high-velocity oxygen-fuel spray deposition.