Origins of Time-Dependent Springback in Aluminum

Origins of Time-Dependent Springback in Aluminum

PROJECT NUMBER: 75 | AUTHOR: Dawson Tong, Metallurgical and Materials Engineering

MENTOR: Kester Clarke, Metallurgical and Materials Engineering

ABSTRACT

After the forming of sheet materials such as aluminum, magnesium, and titanium, a phenomenon known as time-dependent springback may occur. The material tends to no longer hold the formed dimensions right after forming and continues to deform from months to years after the process. Companies may then have to re-form the product or in some cases scrap the material which results in a loss of time and money. Although there are well known methods for predicting springback amounts, newer stamping methods utilize complex deformation patterns making it difficult to predict final part dimensions. If time-dependent springback can be mitigated, then materials such as aluminum may be utilized more frequently in automobile and aerospace industries. In order to mitigate springback, a better understanding of the origins and mechanisms behind it must be studied.
The main theories currently for aluminum consist of creep, anelastic behavior, and a back stress driven diffusion limited dislocation movement mechanism. Although most of the papers agree on these macroscale mechanisms, many do not go in depth on proving them or investigate microstructural changes occurring within the specimens. To investigate this phenomena draw bend testing is utilized to create similar processing parameters to an industrial forming procedure. The springback was investigated macroscopically to determine amounts on varying thicknesses and compositions of aluminum. Further investigation is still needed on the microscopic mechanisms through varying microscopy techniques.

PRESENTATION

AUTHOR BIOGRAPHY

Dawson Tong is currently a senior undergraduate in the metallurgical and materials engineering department. His research is done under the center for advanced non-ferrous structural alloys. His research has mainly been focused on aluminum sheets as well as die castings. After graduation he will be working for Puget Sound Naval Shipyard as a nuclear engineer.