756 SUMMARY OF CURRENT RESEARCHES RELATING TO 



that of the copper-tin series. The compounds found are Cu^Al, CugAl, 

 and CuAla- In the discussion W. Rosenhain gave results showing the 

 fall in tenacity of certain of the copper-rich alloys with rising tem- 

 perature. Gr. H. Gulliver severely criticised the equilibrium diagram 

 and submitted an amended diagram. The authors claimed that Grulliver's 

 objections were due to misunderstanding of their results. 



Constitution of the Aluminium Bronzes.* — B. E. Curry has de- 

 termined the equilibrium diagram above 400° C, obtaining thermal 

 data entirely from heating curves, thus eliminating super-cooling effects. 

 The thirty-four alloys prepared were also examined microscopically, after 

 annealing of sufficient duration to produce equilibrium. The diagram 

 given differs in important respects from that given by Carpenter and 

 Edwards. Only one compound, CuAL, was found, with six series of 

 solid solutions. Two thermal changes occur below the solidus. 



'&^ 



Tensile Strengths of the Copper -Aluminium Alloys, t — B. E. 

 Curry and S. H. Woods have investigated the relation between 

 constitution and mechanical properties, and give a series of tables of 

 results of tensile tests of alloys in the ranges of composition 0-25 p.c. 

 and 86-10(1 p.c. copper. The test pieces were cast to size in Acheson 

 graphite moulds. The alloys were tested as cast, and after annealing 

 and quenching at various temperatures. Two successive additions of 

 aluminium to molten copper each caused a rise of temperature, showing 

 that the heat evolution is due to heat of solution, and not to oxidation 

 of the aluminium by oxygen dissolved in the copper. The author 

 concludes that (a) in the aluminium-rich series (1) the maximum 

 dependable strength occurs in the neighbourhood of the 10 p.c. copper 

 alloy ; (2) annealing at 400° C. for 8-6 days reduces tensile strength, 

 and increases ductihty ; {b) in the copper-rich alloys (1) with more 

 than 92 p.c. copper, annealing has little effect ; (2) with 89-91 p.c. 

 copper the mechanical properties are considerably affected by heat treat- 

 ment ; (3) alloys with less than 90 p.c. copper are brittle and unreliable. 



Methods of Testing".^ — This paper contains a description of the 

 methods elaborated by the International Committees appointed by the 

 Association, with the unification of testing methods as its aim. The 

 length (I) of a tensile test-piece is calculated according to the formula 

 I = n ^/ f, f being the area of cross-section, and n a coefficient, for 

 which the value 11 "3 has been adopted in many countries. Elastic 

 limit may be considered to lie at the point where' the permanent 

 deformation is about O'OOl p.c. Limit of proportionality is to be 

 regarded as the stress up to which equal increments of about 100 kilos, 

 per sq. cm. produce equal elongation. The apparent elastic limit is to 

 be taken as the stress which causes a permanent elongation of between 

 • 2 and • 5 p.c. 



' Journ. PhTs. Chem., xi. (1907) pp. 425-36 {2 figs.). 



t Tom. cit.,pp. 461-91 (7 figs.). 



J Methods of testing metals raid alloys ; hj'draulic cements and woods ; clay, 

 stoneware and cement pipes. Recommended by the 4th (Brussels) Congress of 

 the International Association for Testing Materials, 1906. London : E. & F. N. 

 Spon, 54 pp. (5 figs.). 



