Oxygen-free copper was extruded in the form of short solid cylinders (25 mm dia × 25 mm long) with reductions of approximately 20 percent and then followed by a compression test restoring the shape of the specimen to nearly the initial state. This process was repeated a number of times and it was found that the strength of the deformed metal did not follow the compression flow curve of the annealed metal but remained substantially lower. This procedure resulted in a temporary weakening of the metal which was attributed to a recovery process. It is thought that by a diligent selection of a forming process this temporary weakening of a metal might be utilized in practice.

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