Crystallization steps in Zr- and Hf-based bulk metallic glasses

Different Zr- and Hf-based amorphous alloys were prepared by melt-spinning, mechanical milling and copper mold casting to compare their devitrification behaviour. The perturbed angular correlation technique was applied to characterize the local order in these amorphous samples and its evolution with temperature. The crystallisation process, being a complex mechanism in these multicomponent alloys, is analyzed in detail. At intermediate stages metastable phases and nuclei of intermetallic compounds are found. The hyperfine parameters of the final products are compared with those of well defined crystalline alloys.