Systematics binary alloy systems

The analysis of several pure metals and binary alloys yields generally at least a duplex and in some cases a multilayer structure of the passive film, as depicted schematically in Fig. 19. These systems have been examined with surface analytical methods, mainly XPS, but also ISS in some cases. The systematic variation of the electrochemical preparation parameters gives insight to the related changes of layer composition and layer development, and support a reliable interpretation of the results. Usually the lower valent species are found in the inner part and the higher valent species in the outer part of the passive layer. It is a consequence of the applied potential which of the species is dominating. Higher valent species are formed at sufficiently positive potentials only and may suppress the contribution of the lower... 

By using a systematic procedure to find the relevant element properties representing the alloying behaviour of binary systems, Villars (1983, 1985) defined three expressions for atomic properties which enable systems that form compounds to be separated from those that do not. 

Owing to their numerous actual and potential applications, several ternary and complex systems of these metals, especially of aluminium, have been investigated a few examples of the systematics of Al-Me-X alloys are presented in 5.18 and in Fig. 5.41. Recent contributions to this subject have been given with the study of the systems R-Al-Cu (Riani et al. 2005, and references there in). These rare earth alloys, characterized by the formation of several intermediate phases, are interesting also as raw materials for the preparation of amorphous alloys. Regularities in the trends of their properties have been underlined. The experimental and calculated data relevant to the binary systems Al-Fe, Al-Ni and Fe-Ni have been examined and discussed in a paper concerning the assessment of the ternary Al-Fe-Ni system (Eleno et al. 2006). 

In some cases it is possible to fiilly parameterize a given system from experimental input, as will be done in every example presented in Sec. 3. However, the determination of complete primary parameter sets for every possible element in every possible reference state, as well as the associated secondary sets for the concentration-dependent binary cases, is not an easy task as, in most cases, it would require input that is not available from experiment. Once again, this issue can be properly and systematically dealt with by means of first-principles calculations. For example, reference states can differ from the ground state symmetries of the participating elements in the alloy. In those situations, it is strictly neces-... 

Before the present work, insufficient data were available in the literature for phase equilibria of systems based on Ti-B. There is a large body of data in literature on the properties of titanium-boride materials, but there is no systematic information regarding the specific role(s) of candidate alloying elements. Thus, the present effort was undertaken to explore the role of alloying additions through the study of phase equilibria and alloy properties, as well as their interrelation, from the binary Ti-B system to the Ti-rich portions of ternaries Ti-Al-B and Ti-B-X, further to quaternaries Ti-10 at.% Al-B-X (where X = Si, Ge, Sn, Zr, V, or Nb) and to some multi-component alloys. 

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