The Aluminium Bronzes: A Survey of the Physical and Mechanical Properties of these Materials of Wide Use Available to Purchase

THE demands of modern engineering employing machinery that has to operate at high power, and to include rapidly‐moving units, has forced the metallurgist to depart from the old‐established alloys and to introduce new mixtures to which it is possible to impart specific or enhanced properties by thermal treatments. This aspect of metallurgy has also been given impetus by the demand for reliability, whether in factory plant or the fabricated product. This becomes obvious when it is realised, on the one hand, that the basis of all systemised workshops is the maintenance of continuity in output and an ever‐increasing production; and, on the other, that the failure of even a minor accessory may cause disaster with loss of material, labour or human life. Thus, it no longer occurs that one regards the ferrous metals only as being manipulable by selected heat treatments, and, in the non‐ferrous scries, annealing to be the only means of modification by heat. To‐day, various copper‐rich alloys are available that are susceptible to hardening and tempering processes closely similar to those long since employed for steels. Those containing beryllium and aluminium have been the most exploited. However, the reluctance with which the engineer accepts the advantages offered by these developments is understandable, because the information appertaining to the subject is not always available in a form which enables him to appreciate the economies to be accrued. Further, he often prefers production to be straightforward, using raw materials in the “as‐received” condition, rather than to introduce processes, the value of which has not been elucidated. Yet this is a situation that cannot be tolerated indefinitely, if economies in material weights and dimensions and increased service life are mutually to be secured. It is, therefore, from this angle that the study and comprehension of the properties and possibilities of aluminium bronze cannot be ignored.