Abstract
The crystallization behavior of the Mg–Al alloy (initial ratio Mg : Al=17:12) prepared by ball-milling (BM) was studied by means of X-ray diffractometry (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the case of a short BM time (18ks), we could prepare the mixture of nano-sized Mg and Al grains. And the post annealing of the mixtures at even T<373 K yielded formation of the fine and low strained Mg17Al12 phase. In fact, the DSC analysis showed that only the sample after 18 ks of BM had a distinct exothermic peak at 373 K, corresponding to the formation of the Mg17Al12 and consisted of the compound from nano Mg and Al grains. The samples prepared for longer BM (144ks) did not show equivalent the formation peak time. These samples were composed of nano-sized Mg17Al12 phase with heavy strained due to mechanical energy. In addition, the Mg17Al12 synthesized from the sample after 18 ks of BM is superior in hydrogen properties to the sample after 144 ks of BM.
