The effect of silicon on the strengthening and work hardening of aluminum at room temperature

Solution hardening of Al–Si alloys at room temperature was investigated by tensile tests of several aluminum alloys containing various amounts of Si in solution but fabricated from the same commercially pure base material. It is found that Si has a weak strengthening effect but a significant impact on the work hardening. The strengthening was found to be very sensitive to water quenching, which enhances the solute strengthening. Despite the low strengthening effect, the Portevin–Le Chatelier effect was clearly observed during the tension of an alloy containing 0.4 at% Si, suggesting the occurrence of dynamic strain ageing due to surprisingly low levels of Si in solid solution.