An Optimized Aluminum Alloy (X6111) for Auto Body Sheet Applications

The influence on properties of various alloying elements in the principal aluminum alloys used for external auto body components has been studied and from the results an alloy with improved characteristics has been devised. The properties evaluated were strength, formability, age-hardening response and corrosion resistance.

The fabrication practices were also examined and the best procedures to maximize properties were developed. The alloy has been formulated to provide the necessary formability requirements encountered in the production of body panels, while still obtaining a high yield strength after paint bake for good denting resistance. The result is a sheet alloy with slightly reduced yield strength but better formability and less susceptibility to spring back than 2036, 2038 and 6010 in the T4 temper and with an excellent response to paint bake treatments. The corrosion resistance of the new alloy is superior to that of 2036 and 2038 and is comparable to that of 6009 and 6010.