INFLUENCE OF DISLOCATION STRESS ON THE CORROSION BEHAVIOR OF (111) AND (123) SURFACE PLANE OF ALUMINUM SINGLE CRYSTAL

摘要

The corrosion behaviors of (111) and (123) surface plane of high purity aluminum single-crystal were observed after chemical etching. The amount of etching pits on (111) plane was higher than that on (123) plane, and the average distance of the etching pits were 29.13μm and 37.37μm on (111) and (123) plane respectively which should be larger than the average distance between dislocation ends where they emerged at the surface. The tensile stresses on (111) and (123) plane were calculated according to the stress fields of different edge and screw dislocations. It is deduced that the etching pits nucleate at the sites where the-dislocations meet the surface, which is promoted by the tensile stresses around the dislocations. The tensile stress fluctuation induced by dislocation stress fields is stronger on (111) plane than that on (123), which induces higher nucleation rate on (111) surface plane.