Bending angle of dislocation pinned by an obstacle and the Friedel relation

Abstract

The Friedel relation between the effective stress and the average length of dislocation segments agrees with the Fleischer relation () in the L ₀/L versus φ ₀ curve within 150° ≤ φ ₀ ≤ 180°, where L ₀ is the average spacing of impurities on a slip plane, L is the impurities along a dislocation and φ ₀ is the angle at which the dislocation embraces the impurity at a temperature of 0 K. Therefore, it was considered that the Friedel relation is suitable for impurity obstacles that impede the dislocation above φ ₀ of about 150° during steady and plastic deformation. In addition, it was confirmed from the value of φ ₀ that the Friedel relation is appropriate for the interaction between a dislocation and the impurity in alkali halides doped with monovalent impurities. This is based on the data obtained by strain-rate cycling tests associated with ultrasonic oscillation at 80 to 300 K.

Keywords:

• mobile dislocation
• thermal obstacle
• Friedel relation
• Fleischer relation