THERMALLY-ACTIVATED DEFORMATION OF THE BODY CENTERED CUBIC METALS AT LOW TEMPERATURES
Abstract
The activation energy H, activation volume v*, and frequency factor nu for the deformation of Group VA(V, Cb, Ta) and Group VIA(Cr, Mo, W) metals were determined as a function of the thermal component of the stress, tau*, from data in the literature on the interrelationship of stress, temperature, and strain rate. It was found that H0 (tau* app to 0) 0.1 mu b cubed, where mu is the shear modulus and b is the Burgers vector. Also, v* app to 50 b cubed at tau* 2 kg/sq mm, increasing rapidly to values in excess of 100 b cubed at lower stresses and decreasing to 2 - 5 b cubed at high stresses, and nu 10 to the 4th power 10 to the 11th power 1/sec. The activation energy and volume as a function of stress were independent of structure, indicating that the rate- controlling mechanism for the deformation of body centered cubic metals is overcoming the Pei erls-Nabarro force. TPERIMENTA# DATA WERE IN AGREEMENT WITH Seeger's model for the thermally activated nucleation of kinks. The kink energy and the Peierls-Nabarro energy and stress derived from the data were 3 - 4 x 1/ 100 mu b cubed, 2 - 4 x 1/1000 mu b cubed and 0.6 - 1.5 x 1/100 mu, respectively.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 05, 1963
- Accession Number
- AD0402793
Entities
People
- H. Conrad
- W. Hayes
Organizations
- The Aerospace Corporation