Work-Hardening and Strain Rate Sensitivity of Flow Stress in High Purity Ice Single Crystals.

• Main Author: Parameswaran,V. R.
• Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H
• Format: Text
• Language: English
• Published: 1975
• Subjects: Snow; Ice and Permafrost; Crystallography; *Single crystals; *Ice; Strain rate; High purity; Dislocations; Hardening; Hardness; Motion; Plastic properties; Laboratory tests; Flow; Compression; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA018015; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA018015

Single crystals of high purity ice deformed by uniaxial compression on an Instron machine showed remarkable work- hardening after about 8% strain. By changing the strain rate during compression tests in the plastic region of the stress-strain curve, an apparent activation volume V* and a dislocation mobility exponent m were calculated from the strain rate sensitivity of flow stress. The large work-hardening and the rapid increase in the value of m beyond about 10% strain indicate that the plastic flow in this region is controlled by dislocation intersections and nonconservative motion of jogs. (Author)