The diffraction of X-rays by age-hardening aluminium copper alloys.

Abstract

The object of this paper is to draw attention to certain peculiarities in the X-ray diffraction spectra obtained from single crystals of an alloy of aluminium with 4% by weight of copper. The experiments described below were carried out during an investigation into the property of age-hardening exhibited by these alloys, in the hope that some light would be throuwn on the processes preceding precipitation of the compound CuAl 2 , which are generally regarded as being the cause of the hardening in alloys of the Duralumin class, of which the simple 4% copper alloy is the prototype. The material used in the investigation was prepared from aluminium of high purity and after casting the ingots were forged and then draws into wires of 1 mm. diameter. Pieces of the wire after annealing at 500° C. contained crystals of sufficient size (2-5 mm. in length) for X-ray examination by the oscillating crystal and Laue methods.