A Study into the Effects of Electric Fields and Currents on the Aging and Quench Hardening of Steels
Abstract
Studies were conducted on the effects of an internal electric current and an external electric field on the mechanical properties of metals and on solid state transformations therein, giving attention to the quench aging of a low-carbon steel and the hardenability of a tool steel. A continuous d.c. current of approx. 10(3) A/cm2 ad the rate of quench aging at 80 deg C, whereas an a.c. current of the same magnitude and a frequency of 50-100 Hz dramatically suppressed the aging. An external electric field of approx. 14 kV/cm retarded the quench aging by altering the nature of the precipitation process. Regarding hardenability, an external electric field of 1 kV/cm increased the hardenability of a tool steel by shifting the CT curve to longer times. It was further established during the present studies that high density d.c. pulses (= or > 10(3) A/cm2 of approx. 100 microns duration) increased the plastic strain rate of metals by orders of magnitude, increased fatigue life and enhanced the rates of recovery and recrystallization but retarded grain growth. An external electric field of - 1 kV/cm reduced the flow stress during the superplastic deformation of 7475 Al, retarded grain growth and significantly reduced the cavitation. The effects of the electric current and external field on the various phenomena are explained in terms of their influence on the mobility of point (vacancies and solute atoms) and line (dislocation) crystal defects. .... Electric current, Electric field, Electric charge, Quench aging, Hardenability, Plastic deformation, Flow stress, Dislocation mobility, Recovery, Recrystallization grain growth, Fatigue, Superplasticity, Cavitation, Carbon diffusion, Vacancy migration, Cooling-Transformation (CT) curve, Jominy end-quench, Precipitate- free zone, Dispersoid-free zone.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 1993
- Accession Number
- ADA260228
Entities
People
- Hans Conrad
Organizations
- North Carolina State University