The effect of changes in both the direction of tensile stress and the strain rate upon the plastic behavior and microstructure of aluminum has been investigated. The reduction in strain-hardening rate following a strain-path change was influenced by the strain rate prior to and after the change; higher strain rates in the first stage and lower rates in the second stage decreased the initial transient hardening rate. The introduction of a large path change significantly reduced the effect of strain-rate changes on the strain-hardening rate observed in testing without changing the tensile axis. Evidence of cell wall disruption following a path change was found, and this mechanism combined with effects of cell wall orientation can qualitatively explain the removal of the rate sensitivity of hardening rate because the usual recovery events in cell walls no longer have a dominant influence on flow stress development.