ON THE EFFECT OF A MAGNETIC-FIELD ON THE YIELD-POINT AND KINETICS OF MACROPLASTICITY IN LIF CRYSTALS

A strong effect of a static magnetic field B on active deformation kin etics (<epsilon>over dot>=const) in LiF crystals is observed. This is a threshold effect with respect to B and <(epsilon)over dot>; it is ob served only for B>B-c (B similar or equal to 0.4 T) and <(epsilon)over dot><<(epsilon)over dot (c)> (<(epsilon)over dot (c)>approximate to 1 0(-4) s(-1)). Magnetic sensitivity is exhibited by the yield stress wh ich decreases by approximately a factor of 1.5 for stress tau(y), whic h decreases by approximately a factor of 1.5 for B=0.48 T, and by the stage-II and stage-III hardening coefficients theta(II) and theta(III) , the former decreasing and the latter increasing in a magnetic field. A physical interpretation is proposed for the observed behavior. (C) 1997 American Institute of Physics.