From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
General description of the alloy Beryllium Bronze, detailing its composition and mechanical properties.
| Identifier | ExFiles\Box 149\4\ scan0339 | |
| Date | 31th May 1937 guessed | |
| JAMES BOOTH & COMPANY (1915) LIMITED BERYLLIUM BRONZE. GENERAL DESCRIPTION. "BERYLLIUM BRONZE" is the name given to the alloy which contains 97.5 per cent of copper and 2.5 per cent of beryllium. In America the material is usually referred to as "BERYLLIUM COPPER". The phenomenal effect wrought upon the mechanical properties of copper by the admixture of this small proportion of beryllium constitutes what is the major discovery of our time in non-ferrous metallurgy. It is necessary to say at the outset that beryllium bronze is not a laboratory product, but one that has already been extensively applied in this country in those fields where its phenomenal mechanical properties are peculiarly applicable. Already this amazing material has its imitators, which seem primarily intended to be cheap, and, indeed which succeed in this objective. But, when the physical and mechanical properties are considered, beryllium bronze remains incomparably superior to any other non-ferrous alloy in use in the world to-day. The purely mechanical properties of copper are not remarkable and this metal commends itself to industrial use mainly on the grounds of its high electrical and thermal conductivity. Electrolytic copper has a 0.1 per cent proof stress of about 4 tons per square inch, and a maximum stress of 15 to 15.5 tons per square inch, with an elongation of 50 per cent. When, by the addition of 2½ per cent of the metal beryllium, it becomes beryllium bronze, its mechanical properties are increased to the order of - 0.1 per cent proof stress 60 - 70 tons per square inch, a maximum stress of 80 - 100 tons per square inch, and an elongation of 5 - 2 per cent. Thus, by the addition of this relatively small proportion of beryllium (2.5 per cent), the tensile strength of copper is increased by 430 - 550 per cent. Than this, there is no more phenomenal change in the world of applied metallurgy. The very small amount of beryllium required to produce this effect is fortunate from the commercial standpoint, for otherwise, the present high cost of pure beryllium would make the alloy prohibitively expensive. As it is, although beryllium bronze is not a cheap material when considered in terms of first cost, it is by no means prohibitive. When, in addition, its remarkable endurance in certain applications be considered, it may be actually cheap in the best sense of the word, because it must many times outlive less costly materials. | ||