急冷Cu結晶(111)面におけるエッチビークの形成について

Abstract

The (111) surfaces of copper crystals rapidly-cooled from 1273 K in a purified Ar atmosphere were etched in three kinds of dislocation etchants, and the etch patterns were studied by means of optical and electron microscopies. From the replica examinations with an optical microscope dark and deep etch pits with beaks were found in addition to the normal dislocation etch pits. Their densities amounted to 107–108 m−2, two orders of magnitude less than those of the normal ones. When the crystal was etched for a long period, the etch pits with beaks gradually changed from sharply-pointed and deep ones to flat-bottomed and shallow ones, and finally disappeared, while small ones newly appeared at some other places. It is noted that such etch pits cannot be observed in copper crystals slowly-cooled from the same temperature in Ar atmosphere. Detailed observations of the replicas with an electron microscope revealed that the beaks extended into the inside of the crystal from the apex of the etch pits along the oblique [110] (otherwise [101] or [011]) direction though details of their shapes varied with changing etching solution. Defect ribbons with a some-what complicated structure were observed in thin films obtained from the rapidly-cooled copper crystal, which might presumably be associated with the etch beaks.