A Study of Conformal Phases in Metal Alloy Systems

Citation

Pietrokowsky, Paul (1959) A Study of Conformal Phases in Metal Alloy Systems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/J221-2G70. https://resolver.caltech.edu/CaltechETD:etd-02172006-113424

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The atomic motifs of the intermediate phases TiAu4 have been investigated. Both crystal structures are tetragonal. Lattice parameters of TiAu4, 80 atomic percent gold, are a2 = b2 = 6.460(5) [angstroms] and c2 = 3.976(5) [angstroms]. There are ten atoms in the unit cell; two titanium atoms were placed in positions (a) and eight gold atoms were placed in (h) of space group [...]. The positional parameters were determined to be [...]. Lattice parameters of TiPt8 are [...]. The unit cell contains eighteen atoms. Space group [...] was used: the two titanium atoms were placed in (a), eight gold atoms in (h) with parameter x1, and eight gold atoms in (i) with parameter x2. The positional parameters were determined to be x1 = 0.333 and x2 = 0.327. The use of conformal transformations in these investigations is discussed. A result of this investigation has been the redetermination of the partial constitution diagram TiAu2-Au. Two intermediate phases were established. The phase TiAu2 is congruent melting. It is tetragonal with lattice parameters a = b = 3.4192 [angstroms] and c = 8.513 [angstroms]. The crystal structure has been determined. The two titanium atoms are in (a), of space group [...], and the four gold atoms are in (e) with z = 0.337. A second intermediate phase, TiAu4, displays a hidden maximum. The solubility limit of titanium in gold has been studied as a function of temperature. In addition, the region of homogeneity of TiAu4 has been investigated. The alloys TiFe, TiCo, and TiNi have been investigated by X-ray diffraction methods. Evidence for long-range order in these phases has been established. Thus these alloys are of the CsCl type crystal structure type.

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