On Some Phenomena Related with Anneal Hardening of α Solid Solution of Copper Alloys. (On Anneal Hardening of Several Copper Alloys (5th Report))

Abstract

When a heavily drawn specimen of α-brass is cold-rolled, it undergoes first a hardening and then a softening with the progress of rolling. This hardening will be called “secondary work hardening”. It is obtained by slight application of a secondary working differing in type from the primary, and in addition, it is marked only in such alloys as exhibiting conspicuous anneal-hardening. It may be inferred that anneal hardening and secondary work-hardening are induced by nearly the same cause, that is, both hardenings are similar phenomena due to destruction of the as-primary-deformation structure. They are dissimilar only in that in the former, the destruction is caused by internal stress and thermal diffusion, while in the latter, it is by forced deformation. The deformation structure above mentioned may be interpreted by assuming that the structure is marked in anisotropy in anelastic effect, and the effect is chiefly induced by the back stress due to the internal stress of vacancies which show anisotropic arrangement and shape depending on working condition. With the progress of different-type secondary working, the destroyed structure transforms gradually to the structure specific to the secondary working, causing softening.