Single-phase region alloy

DEF. When the constitution point lies in a single-phase region, the alloy consists of a single, homogeneous, phase. Its composition must (obviously) be that of the alloy. The phase composition and the alloy composition coincide in single-phase fields. 

The high-pressure study on the Ti-H alloys showed stress-strain properties are not the only ones which are affected by pressure, but phase equilibria are also strongly dependent on this parameter . A new ( -phase and a corresponding single phase region in the isobaric T — C section of the T — P — C phase diagram appear in the... 

The general thermodynamic treatment of binary systems which involve the incorporation of an electroactive species into a solid alloy electrode under the assumption of complete equilibrium was presented by Weppner and Huggins [19-21], Under these conditions the Gibbs Phase Rule specifies that the electrochemical potential varies with composition in the single-phase regions of a binary phase diagram, and is composition-independent in two-phase regions if the temperature and total pressure are kept constant. 

Because of the interest in its use in elevated-temperature molten salt electrolyte batteries, one of the first binary alloy systems studied in detail was the lithium-aluminium system. As shown in Fig. 1, the potential-composition behavior shows a long plateau between the lithium-saturated terminal solid solution and the intermediate P phase "LiAl", and a shorter one between the composition limits of the P and y phases, as well as composition-dependent values in the single-phase regions [35], This is as expected for a binary system with complete equilibrium. The potential of the first plateau varies linearly with temperature, as shown in Fig. 2. 

Ike2] Ikeda, M., Komatsu, S., Inoue, K., Hiroyuki, S., Imose, T., Effect of Cr Addition on Tensile Properties of Ti-Fe-Cr 3 Alloys Quenched from 3 Single Phase Region at 1173K ... 

To distinguish between virtual and complex diffusion paths let us consider the model system depicted in Figure 10.5. Diffusion occurs between a and alloys with initial compositions illustrated by points X and Y on the concentration triangle. If we proceed from the approximation of a planar interphase boundary (Kirkaldy and Brown), the diffusion zone morphology depends on where the diffusion path comes after intrusion into the two-phase region. If it comes back to the same single-phase region, this implies just a precipitation zone of isolated precipitates... 

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