260 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Constitution and Treatment of Steel.* — A. Portevin applies the 

 equilibrium diagram of the iron-carbon system to the constitution and 

 thermal treatment of steels and cast irons. The constituents, micro- 

 scopically distinguished in a polished section, may correspond (1) to 

 the phases in stable or labile equilibrium at the ordinary temperature ; 

 (2) to the phases in equilibrium at a higher temperature, preserved 

 unchanged by quenching ; (3) to states of transition between the 

 phases as in (2) and as in (1). The author briefly describes the mode 

 of production of the known constituents, including osmondite, but 

 purposely leaving out of account Benedicks' ferronite and Kourbatoff's 

 troosto-sorbite because so little is known regarding- them. 



■'&"- 



Binary Alloys of Copper, t — R. Sahmen has determined the 

 equilibrium diagrams of the systems cobalt-copper, iron-copper, man- 

 ganese-copper, and magnesium-copper. The component metals of each 

 system are miscible in all proportions in the molten state. In the 

 cobalt-copper and iron-copper systems, mixed crystals occur at both 

 ends of the diagram. Temperatures of magnetic and thermal trans- 

 formations were determined in these series. Manganese and copper 

 form a continuous series of mixed crystals with a minimum freezing-point 

 at 866° C. and about 65 p.c. copper. Magnesium and copper form two 

 compounds, Cu 2 Mg and CuMg 2 , melting-points 797° C. and 570° C. 

 Etching reagents used were ammoniacal solution of hydrogen peroxide, 

 and dilute sulphuric acid, used electrolytically. 



Binary Alloys of Nickel. J — G. Voss gives the results of his 

 determinations of equilibrium diagrams for the binary alloys of nickel 

 with tin, lead, thallium, bismuth, chromium, magnesium, zinc, and 

 cadmium. Tests were made of magnetic permeability, temperatures 

 of magnetic transformation were determined, and the alloys were micro- 

 scopically examined. Owing to the low boiling-points of zinc and 

 cadmium, the diagrams for the systems containing these metals only 

 cover the range, 0-27 p.c. nickel and 0-15 p.c. nickel, respectively. The 

 compounds found were Ni 3 Sn 2 , Ni 3 Sn, Ni 4 Sn. NiBi, NiBi 3 , Ni 2 Mg, 

 NiMg 2 , NiZu 3 , NiCd 4 . With tin, lead, and thallium, nickel is not 

 completely miscible in the liquid state. 



Binary Alloys of Aluminium. §— A. G. C. Gwyer has determined 

 the equilibrium diagrams for the alloys of aluminium with copper, iron, 

 nickel, and cobalt, with which metals aluminium is completely misci I »le in 

 the molten state. Aluminium does not mix in any proportion with lead i >r 

 cadmium : no alloys are formed therefore, and the diagrams for these 

 two binarv systems are the simplest possible. The compounds are 

 CuAl 2 , CuAl, Cu 3 Al, FeAl 3 , NiAl 3 , NiAl,, NiAl. Co 3 Al 13 , Co 2 Al-„ CoAl. 

 Thermal results were confirmed by microscopical examination. The 

 author considers that Carpenter and Edwards assumed the existence of 

 Cu 4 Al on insufficient evidence, and points out that they did not mention 

 'CuAl, though its existence was indicated by their thermal results. A 



* Rev. de Mitallurgie, v. (1908) pp. 24-33 (10 figs.). 

 + Zeitsehr. Anorg. Cbem., lvii. (1908) pp. 1-33 (27 figs.). 

 % Tom. cit., pp. 34-71 (42 figs.). 

 § Tom. cit.,pp. 113-53 (30 figs.). 



