The influence of molybdenum on the γ/’phase in experimental nickel-base superalloys
01 Jan 1972-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science (Springer New York)-Vol. 3, Iss: 4, pp 989-1000
TL;DR: In this paper, the influence of molybdenum on lattice parameters was investigated in wrought nickel-base superalloys containing about 14 at.pct Cr and 6-1/2, 9, or 12 at. pct Ti alloys.
Abstract: The influence of 1, 3, and 5 at. pct Mo on the γ’precipitate has been studied in experimental wrought nickel-base superalloys containing about 14 at. pct Cr and 6-1/2, 9, or 12 at. pct Al, or 2 at. pct Al plus 4 at. pct Ti. Concentrations of all other elements were quite low to limit the observed effects to those of molybdenum alone. Molybdenum markedly increases the γ’ solvus temperature, as determined by the sensitive and relatively simple technique of differential thermal analysis; correspondingly, the weight fraction of γ’ increases with molybdenum additions for a given aging treatment. Molybdenum dissolves extensively in the γ’of the titanium-free alloys, but it dissolves to a considerably smaller extent in the γ’of the titanium-bearing alloys. Molybdenum substitutes for chromium in y’, but does not alter the aluminum or titanium contents of this phase. Lattice parameters of both the matrix and the γ’are increased markedly by molybdenum, in proportion to the molybdenum contents of these phases. The resulting effects on lattice-parameter mismatch correlate rather well with observed γ’morphology, which tends to change from spheroidal to cuboidal in titanium-free alloys, and from cuboidal to spheroidal in 2 at. pct Al-4 at. pct Ti alloys, as molybdenum is added to these alloys.
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Book•
01 Jan 1958
TL;DR: The Handbook of Lattice spacings and structures of metals and alloys as discussed by the authors is a handbook of argumentative essay structure spacing and lattice plane model modified by the incorporation of thermodynamic functions appropriate to the f.c.
Abstract: For the best product experience, a Handbook of of argumentative essay structure spacing Lattice Spacings and Structures of Metals and Alloys ScienceDirect. Get this from a library! A handbook of lattice spacings and structures of metals and alloys. (W B Pearson) Acm metal). Vol. lattice plane model modified by the incorporation of thermodynamic functions appropriate to the f.c.c. Al—Ag solid zones in the alloys. W. B. Pearson, Handbook of Lattice Spacings. Structures of Metals and Alloys.
3,090 citations
TL;DR: In this article, the degree of long range order in the γ′-phase of the nickel-aluminum system was determined as a function of temperature by means of X-rays.
Abstract: The degree of long range order in the γ′-phase of the nickel–aluminum system was determined as a function of temperature by means of X-rays. The measurements were carried out on {h00} single crystals, using a high-temperature vacuum X-ray diffractometer. Two compositions were investigated: stoichiometric Ni3Al and an off-stoichiometric nickel-rich alloy. Complete long-range order was present to within 65°C of the melting point, the highest temperature measured. Line breadth measurements indicated a large, temperature independent anti-phase domain size. From the intensity variation of the 400 reflection with temperature, a Debye temperature of 360°K was deduced. The linear coefficient of thermal expansion between 25 and 800°C was found to be 15 x 10−6 per °C.
61 citations
01 Jan 1971
TL;DR: In this paper, the mismatch between the lattices of austenite and the age-hardening gamma-prime (γ′) precipitates and the resultant coherency strains have a significant influence on the elevated temperature, particularly stress rupture, properties of a nickel-base superalloy.
Abstract: This study was designed to provide a critical test for the postulate that the mismatch between the lattices of austenite (γ) and the age-hardening gamma-prime (γ′) precipitates and the resultant coherency strains have a significant influence on the elevated temperature, particularly stress rupture, properties of a nickel-base superalloy. Two experimental alloys with a base analysis of Ni, 20 Cr, 5.5 Mo were designed with variable titanium and aluminum additions. To discern the effect of mismatch, an alloy without molybdenum was also experimented with. By manipulating the mismatch and volume fraction γ′ by heat treatment and chemistry, it was shown that a lower γ-γ′ mismatch indeed is beneficial to stress rupture life. Importance of volume fraction γ′ on this elevated temperature was also established.
47 citations
13 citations
TL;DR: Slaney as discussed by the authors proposed a new method based on the maximum solubility of individual elements in precipitating phase and the availability of such elements in the alloy to predict the gamma prime.
Abstract: The shortcomings of present methods of prediction are considered and a new method is proposed. This is based upon the maximum solubility of individual elements in the precipitating phase and the availability of such elements in the alloy. The plan of a computer program is suggested and a comparison made between an analyzed and predicted composition of gamma prime. J. S. Slaney is Senior Research Associate with Latrobe Steel Company, Latrobe, Pennsylvania.
4 citations