Defects and their interaction with lubrication in cupping process of recycled aluminum alloy sheet

Abstract

Recycled aluminum will be a significant material choice for automobile body stamping because of its recyclability and low cost. In this paper, the cupping tests and tribological tests were used to study the evolution of defects in forming process and its influence on the properties of recycled aluminum alloy, Failure mechanisms of recycled aluminum alloy were analyzed, as well as the interaction between different lubricant additives and defects under oil lubricating conditions. According to the results, the defects of the recycled aluminum alloy, especially the impurity phase particles, can have negative effects on the properties of the sheets. The impurity phase particles are brittle and are prone to fracture, resulting in stress concentration. In addition, the binding with the matrix is weak, which destroys the continuity and leads to surface strain in the process of material flow, thus adversely affecting the quality of the cup. By physical adhesion and filling of the depressions, MoS2 solid lubrication additive improves forming and friction performance of the cup. The present study indicates how defects affect the cupping properties of recycled aluminum alloys, and it provides a theoretical basis for the improvement of the stamping lubrication process of recycled aluminum alloys.