Eiselstein , D. Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. DOI: Eiselstein and Donald J. Tillack Published Materials Science Superalloys The filing of a patent application for alloy on January 24, , marked the culmination of nearly a decade of research on the basic Ni-Cr-Mo-Nb alloy system.
This paper describes the research and development effort that resulted in the invention of alloy , how some of the problems that were encountered along the way were solved and how numerous variants of the alloy were developed.
One of the remarkable aspects of the research effort is that it also resulted in the invention of alloy… Expand. View via Publisher. Save to Library Save. Create Alert Alert. Share This Paper.
Background Citations. Methods Citations. Figures and Tables from this paper. Manganese Mn 0. Titanium Ti 0. Silver Ag 0. Carbon C 0. Sulphur S 0. Phosphorus P 0. Download Data Sheet. It was hoped that these tests would indicate any tendencies for age-hardening or embrittlement.
They did in spectacular fashion as can be seen from Figure 1 [3]. The net result of these tests was to delay the development of Alloy as attention shifted to the development of a different alloy, namely Alloy By the time development of Alloy resumed, the market for a nickel-based alloy for super critical steam no longer existed.
In the annealed condition, this alloy was only a little stronger than Alloy UNS N ; as such it offered little advantage over existing alloys. To make it more attractive, it was felt that the alloy needed higher room temperature tensile properties. It was the combination of high strength and good corrosion resistance that altered the course of development of the alloy and increased its marketing opportunities.
After several years of discovering how various elements affected the properties of the alloy system, a patent application was submitted on January 24, Eiselstein and J. Gadbut on December 8, The composition has changed slightly since the patent was issued. The present composition for Alloy is shown in Table 1. Even with the disappearance of the super critical steam market, the development of Alloy was still concentrated on its use at high temperature.
Figure 3 shows the effect of niobium on yield strength. It can be seen that in the annealed condition niobium has very little effect on the yield strength. It was already known that molybdenum increased the solid solution strengthening of the alloy. Molybdenum, chromium and especially niobium impart creep strength to the alloy. These effects are shown in Figures 4 and 5.
Aluminium and titanium were intentionally kept low to minimise the age-hardenability of the alloy. It is noted that the solubility of aluminium in the alloy had been determined to be about 0.
Alloy was originally intended to be a solid solution alloy and for the majority of applications it is assumed to behave as one. It is marketed on the basis that its strength is derived from the stiffening effect of molybdenum and niobium on its nickel-chromium matrix; thus precipitation-hardening age-hardening treatments are not required. The exposure times involved were much longer than the 16 hours used in the original screening tests and, whilst this showed that the alloy was age-hardenable, the ageing times required were uneconomically long i.
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