Influence of thermomechanical processing on coarse particles, grain structure, and mechanical properties of Al–Cu alloy rings

Abstract

Rings made of 2219 Al alloy are typically manufactured by multi-directional forging (MDF) and ring rolling at 460 °C, followed by heat treatment. However, this process often results in coarse elongated grains and a large number of coarse Al2Cu particles, resulting in rings with poor mechanical properties. As a strategy to refine the microstructure and improve the mechanical properties, a novel thermomechanical process was tested for ring manufacturing, with MDF at 510 °C and ring rolling at 240 °C. The results showed that use of MDF at higher temperatures resulted in increased spherical shapes and decreased numbers of coarse Al2Cu particles due to more complete dissolution. Decreasing the rolling temperature from 460 °C to 240 °C resulted in finer grain structure due to the increased nucleation ratio of static recrystallization during subsequent solution heat treatment. Samples prepared using this novel process exhibited fine equiaxed grains with sufficient dissolving of coarse Al2Cu particles, thus this method significantly improved the mechanical properties of the prepared material and decreased the anisotropy in three orthogonal directions.

Keywords

• 2219 Al alloy
• Thermomechanical processing
• Coarse particles
• Grain refinement
• Mechanical properties