Influence of Pre-strain on the Mechanical Properties of A6111-T4P Sheet with Bake Hardening

Abstract

A6111 is an aluminum alloy, which exhibits good formability and excellent bake hardening property. This study aimed to reveal the influence of strain path, pre-strain orientation (α) as well as pre-strain level on the mechanical properties of A6111-T4P sheet under bake treatment through uniaxial tension test. (0–5)% pre-strain, 150–170 °C bake temperature and 20–30 min bake time were considered in the study by referring to the actual production process. The results show that both pre-strain level and strain path play significant roles in improving the material properties. In the condition that tensile orientation (β) parallel with pre-strain orientation (β = α), the yield strength can be remarkably improved, and much higher parameter of n in Hockett–Sherby model can be obtained than those when tensile orientation non-parallel with pre-strain orientation (α ≠ β). In addition, when the pre-strain level, paint bake process were settled and β = α, the curves obtained in five tension orientations are similar in the plastic deformation stage.