Nanostructure Formation and Amorphization in Intermetallic Compounds by Severe Plastic Deformation

摘要

Process of nanostructure formation and amorphization by high pressure torsion (HPT) were studied for various intermetallic compounds. In ZrCu after HPT deformation, optical microscopy revealed that numerous shear bands formed running nearly parallel to the shear direction. Partial amorphization was confirmed by X-ray diffraction and TEM observations. Detailed TEM observations revealed localized amorphization within the nano-scale shear bands. For HPT deformation of zone-melted Zr_(50)Cu_(40)Al_(10) the preferential amorphization of ZrCu phase was observed. On the contrary, amorphization was not observed for Ni_3Al even after HPT deformation of 100 turns; the sample remained to be disordered nanocrystalline of about 50 nm. The process and mechanism of the grain refinement and amorphization will be compared and discussed for these intennctallic compounds.