摘要

Ti55.5Cu18.5Ni17.5Al8.5amorphous powders were prepared by a mechanical alloying process. The microstructure, amorphization behavior and hardness of the powders were studied by X-ray diffraction, differential scanning calorimetry, scanning electronic microscopy, transmission electron microscopy, etc. The results show that the microstructure changes obviously with the milling time increasing. Firstly the grain size decreases and nanometric intermetallic appears. Secondly long range disordered structures appear inside the nanometric intermetallics with further grinding. Finally the intermetallics are separated into many smaller parts by the disordered structure and then amorphized. The mechanism of amorphization was studied from the atomic scale. The result indicates that the main reason of amorphization is that the severe plastic deformation occurs during high energy ball milling, which results in high density dislocations and large lattice distortions, and eventually leads to the long range disordered structure and amorphous structure. Owing to work hardening and amorphization during ball milling, the hardness of alloy increases significantly with grinding.

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