EFFECT OF CYCLIC HEAT TREATMENT ON THE DIMENSIONAL STABILITY OF METALS AND ALLOYS WHEN A LOAD IS CONTINUOUSLY APPLIED

Abstract : Slight tension to specimens of uranium, aluminum, zinc, and alpha and beta-brass during cyclic heat treatment (c.h.t.) produces considerable residual deformation, which substantially exceeds in value (sometimes by several times) the total deformation from creep and from c.h.t. without application of load. Cyclic heat treatment of transverse specimens of textured sheet uranium in the alpha-phase temperature region, and also of beta-brass without tension, causes contraction of the specimens, but with small external tension causes considerable elongation on their part in the direction in which the external force acts. Cyclic heat treatment of uranium with a continuously applied load and a transition through the point of phase transformation alpha to beta the residual plastic deformation increases in comparison with the deformation resulting from c.h.t. within the limits of the alpha-region. In alpha + beta brass the residual deformation resulting from tests for creep alone considerably exceeds deformation under the in-fluence of c.h.t. with a continuously applied load. The dimensional change of the specimens is directed toward the action of the applied external force.