Comparison of the influence of Si and Fe in 99.999% purity aluminum and in commercial-purity aluminum

It is found that in tensile tests 99.999% purity aluminum with additions of about 0.1 wt.% Fe and Si is similar to 99.8% commercial-purity aluminum, suggesting that the strength and work hardening is controlled by Fe and Si, i.e. that the other trace elements play a minor role.