Precipitation strengthening behavior of Al-Li single crystals

The precipitation strengthening behavior of Al-Li single crystals has been studied using compression test and transmission electron microscopy. The strengthening behavior of Al-Li single crystals during the early stage of aging is well described by a recent version of order hardening theory for a weak obstacle regime in a dilute solution. The interpretation of experimental data differs depending on the exact configuration of the trailing dislocation in the dislocation pair. Experimental results are best interpreted by the equation derived on the assumption that the trailing dislocation completely pulls off from the encountering particles. The antiphase boundary energy is determined to be 0.118 J m(-2), which is in reasonable agreement with that obtained from the measurement of critical loop diameter for the transition from shearing to looping, and from the measurement of dislocation pair spacings.