Ternary Alloy Phase Research Articles

Some phases in ternary alloys of titanium, zirconium, and hafnium, with a MgAgAs or AlCu 2Mn type structure

Some phases in ternary alloys of titanium, zirconium, and hafnium, with a MgAgAs or AlCu 2Mn type structure

Alloy Chemistry of od (B-U)-Related Phases IV. Al5, o and X Phases in Ternary Alloys of Refractory Metals with Gallium

Alloy Chemistry of od (B-U)-Related Phases IV. Al5, o and X Phases in Ternary Alloys of Refractory Metals with Gallium

On the decomposition of the beta phase in titanium alloys

A systematic analysis is made of the possible free energy diagrams for a binary titanium alloy consisting of a metastable beta phase, which tends to form either the alpha or the omega phase, or both. The predictions based on each of the possible free energy diagram configurations are compared with the available experimental data. Arguments are developed to show that it should be possible to nucleate an omega phase having an initial solute content less than the metastable equilibrium value and not necessarily a higher solute concentration, as suggested by other investigators. It is further shown that the observed precipitation of a solute-lean beta phase in certain binary and ternary beta alloys cannot be explained in terms of an ordinary miscibility gap resulting from a preference for bonds between like atoms rather than bonds between unlike atoms. An explanation is suggested on the basis of an early model proposed by M. K. McQuillan in which the electronic structure of the titanium atom can change with temperature leading to two possible types of bonding behaviour.

Study of Heat Treatments for Low Coercive Force 14 to 17% Aluminum Iron Alloys

A study was made of the effects of atmosphere, temperature of initial annealing, and composition on the coercive force of 14 to 17% Al-Fe alloys. A combined effect of heat treatment atmosphere and temperature of initial annealing is shown to exist in this alloy region, and is discussed in terms of a possible influence of purification and atomic ordering. The unique feature of these alloys is that heat treatments in air at 900°C produce lower coercive force values than heat treatments in dry hydrogen at the same temperature. This factor would make the heat treatments of these alloys more economical than those of other standard high-permeability alloys. Observations made on the binary Al-Fe iron alloys apply to the heat treatment of Al-Fe alloys containing ternary additions. These observations also show that the heat treatment controls both the grain size and the distribution of the second phase in ternary alloys, which in turn affect the magnetic properties.

The structure of the intermetallic phase θ(Cr-Al)

The monoclinic theta -phase in the chromium-aluminum system was shown to be isomorphous with alpha '(V-Al). The structure was refined and the interatomic distances are discussed and compared with those in alpha '(V - Al) and with those in two ternary alloy phases containing chromium and aluminum. (auth)

A transitional h.c.p. phase in the γ → α transformation in certain Fe-Base alloys

The transitional h.c.p. ε phase of martensitic nature in Fe-Mn alloys has been shown not to be unique to this system but to form also in ternary Fe-Mn alloys containing Ni, Cr, Co or C. Carbon which had the greatest effect on the transformation characteristics, depressed the M d and M 3 points of the γ → ε and γ → α 2 or ε → α 2 transformations. In Fe-Ni alloys, noε phase was detected in 8% and 19% nickel alloys and it is concluded from this and other published work that this phase does not form in the Fe-Ni system. A study of certain Fe-Ni-Cr alloys confirmed that a total Ni + Cr content of more than about 24% was necessary for ε to form. A study was also made of the formation and decomposition of ε in a commercial 18% Cr, 8% Ni alloy steel. A similarity was noted between the microstructure of f.c.c. + h.c.p. phases in binary and ternary Fe-Mn alloys and Fe-Ni-Cr alloys and that of similar phases in several non-ferrous alloys, in some of which, at least, the h.c.p. phase has formed martensitically.