Accession Number:

ADA209218

Title:

A Study Into the Mechanism(s) for the Electroplastic Effect in Metals and Its Application to Metalworking, Processing and Fatigue

Descriptive Note:

Final rept. 20 Nov 1985-19 Nov 1988

Corporate Author:

NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s):

Report Date:

1989-03-10

Pagination or Media Count:

52.0

Abstract:

The effects of high-density electric current pulses and a continuous external d.c. electric field on the behavior of metals and alloys was investigated. The theoretical basis for the effects of the current pulses was considered, giving special attention to an electron wind-assisted dislocation motion. It was determined that high-density electric current pulses significantly increased a the plastic strain rate in unidirectional straining at low homologous temperatures, b the fatigue life, c the rates of recovery and recrystallization and d the transformation of amorphous alloys. It is proposed that an important factor in the effects produced by the current pulses is the influence of an electron wind on the motion of the atoms and dislocations involved. The application of a continuous external d.c. electric field of approx. 1 kVcm retarded the following phenomena a recovery and recrystallization of cold worked Al and Cu, b grain growth and the formation of cavities during superplastic deformation of the 7475 Al alloy, and c quench aging, bainite formation and tempering of steels. The electric field however increased the rates of recovery and recrystallization of the superalloy Ni3Al and the rate of austenization of a tool steel. The effects of the field occurred throughout the bulk of the 1-3 mm thick specimens and not just at the surface, and appear to be associated with the directed atomic mobility produced by a field.

Subject Categories:

  • Properties of Metals and Alloys
  • Fabrication Metallurgy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE