Фазовая диаграмма системы Pb-Ti

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Pb-Ti (Lead-Titanium) J.L. Murray The equilibrium solid phases of the Ti-Pb system are (1) the bcc (bTi), cph ( aTi), and (Pb) solid solutions; the maximum solubilities of Pb in (bTi) and ( aTi), respectively, are 16 and 4.2 с 0.2 at.% [55Far]; (2) Ti4Pb, with the ordered hexagonal D019 structure [51Now] with ideal stoichiometry Ti3Pb and a small homogeneity range; and (3) an additional intermetallic phase shown by X- ray diffraction to be neither Ti4Pb nor (Pb), but its composition and structure are otherwise unknown. The stoichiometry Ti2Pb is the most likely, based on analogy with the Ti-Bi system. The Ti-Pb phase diagram is known only approximately and only in the range 0 to 40 at.% Pb. A preliminary X-ray and microscopic study of the range 12 to 100 at.% Pb was made by [51Now], using sintered compacts. One intermetallic phase, Ti4Pb, was found. [55Far] examined the region 0 to 35 at.% Pb using microscopy, X-ray diffraction, and visual observation of melting. Ti4Pb was verified, and evidence was found for an additional intermetallic phase. The assessed phase diagram is based entirely on the work of [55Far] and is essentially identical to that of [Hansen]. Dashed lines indicate that quantitative phase boundary data are not available, or that the boundary requires further experimental work. The liquidus and solidus temperatures were taken as the temperature at which rounding of the corners of the specimen occurred and the temperature at which the alloy flowed freely [55Far]. Liquidus and solidus temperatures were assigned an accuracy of с10 C. The temperature of the peritectic reaction L + (bTi) = Ti4Pb was reported as 1305 с 10 C, based on melting point data and the microstructure of a 15.8 at.% Pb alloy equilibrated at 1300 C. The reaction of L, Ti4Pb, and Ti2Pb was tentatively identified as a eutectic reaction, based on microstructures of as-cast alloys, but its temperature was not determined. The (bTi)/(bTi) + Ti4Pb boundary was based on microstructures of samples equilibrated at temperatures between 950 and 1200 C. 51Now: H. Nowotny and J. Pesl, Monatsh. Chem., 82,344-347 (1951) in German. 55Far: P. Farrar and H. Margolin, Trans. AIME, 203, 101-104 (1955). Published in Phase Diagrams of Binary Titanium Alloys, 1987, and Bull. Alloy Phase Diagrams, 5(6), Dec 1984. Complete evaluation contains 2 figures, 2 tables, and 6 references. Special Points of the Ti-Pb System