Modeling of residual stress evolution of 7050 aluminium alloy component during heat treatment and cold forming

Abstract

A thermal mechanical coupling numerical model of 7050 aluminium alloy was established using the Hansel-Spittel constitutive model. The stress state of the samples during quenching and cold deformation was analyzed using the finite element simulation technology at first, which is in good accordance with the measured result by ultrasonic test. Then, residual stress evolution rule during heat treatment and cold deformation of an aluminium component with rib structure was studied and ultrasonic residual stress inspection and matching deformation verification were carried out on the structural component. The results show that residual stress after quenching is in the state of external compression and internal tension. The reduction degree of quenching induced residual stress by different cold deformation methods is obviously different. For cold compression, when deformation exceeds 2%, compression on the web obviously improves stress state of the whole web region while compression on the lib has relatively less improvement. For cold stretching, 3% deformation can effectively improve the stress uniformity for both web region and lib region. After cold stretching, the distortion during machining can be obviously improved.

Keywords

• 7050 aluminium alloy
• residual stress
• cold deformation
• thermal mechanical coupling simulation