Micro and sub-micro morphology of Mg65Cu25Y10 bulk amorphous alloy containing primary crystalline phases
(1. Shanghai Key Laboratory of D&A for Metal-Functional Materials, Tongji University, Shanghai 200092, China;
2. School of Materials Science and Engineering, Tongji University, Shanghai 200092, China)
2. School of Materials Science and Engineering, Tongji University, Shanghai 200092, China)
Abstract: Acoustic-frequency induction melting together with rapid quenching was used to prepare Mg65Cu25Y10 bulk amorphous alloy containing primary crystalline phases. Transmission electron microscopy (TEM), X-ray diffractometry (XRD), environmental scanning electron microscopy (ESEM) and atomic force microscopy (AFM) were used to study the amorphization and morphology of the prepared alloy. Under micro condition, the sample alloy is composed of amorphous structure with cauliflorate shape, primary CuMg2 dendrite phase, mixed primary CuMg2 and Cu2Y crystalline phases, as well as Mg phase with small size. Further study under sub-micro condition shows that, the planar amorphous structure of cauliflorate shape is composed of the three-dimensional sub-micro morphology of “bulge-concavity” pattern, which extends into the space in terms of certain period. It is estimated that the major factors influencing the micro and sub-micro morphologies of amorphous alloy are its super-cooling liquid structure, rapid quenching transformation, as well as the melting conditions.
Key words: Mg-based amorphous alloys; induction melting; rapid quenching; morphology