Amorphous copper formation and related phenomena at ultrahigh pressure

Oxygen free high conductivity (OFHC) copper was slowly sheared at ultrahigh pressure at room temperature. Its transmission electron diffraction pattern (TEM diffraction pattern) showed three diffuse halo rings. Transmission electron micrographs (TEM) corresponding to this pattern showed neither dislocation nor grain boundary. These results indicate the formation of an amorphous state. This state remains at atmospheric pressure. Another TEM diffraction pattern that indicates an intermediate structure between the above amorphous state and crystalline copper was also observed.