Abstract
Alloy 2100 GT has been developed for use in the combustors of gas turbines. The improved high-temperature properties of the alloy should allow the metal temperature of the combustion chamber to be increased, which would provide the opportunity of increasing the efficiency, lowering emissions, and decreasing fuel consumption. This alloy is a cobalt, tungsten, and molybdenum-free Ni-base super-alloy. It contains as major alloying elements 25 wt.-% chromium, 8 wt.-% tantalum, 3 wt.-% aluminium, 0.3 wt.-% carbon and 0.1 wt.-% yttrium. High-temperature strength is achieved by solid solution strengthening by tantalum, carbide hardening due to the formation of primary precipitated tantalum carbides and γ'-precipitation hardening by aluminium and tantalum. In spite of the small grain size creep rupture strength and stress to produce 0.1 % creep is significantly increased in comparison to superalloys being in use today. Superior oxidation resistance up to 1200 °C and corrosion behaviour under deposits of sulphates up to 850 °C is given by the formation of a very thin and tightly adherent alumina scale due to an aluminium content of approximately 3.0 wt.-%, which is remarkably high for a wrought alloy, and additions of yttrium to improve spallation resistance under cycling conditions. Welding can easily be accomplished. The matching filler metal is recommended because it provides mechanical strength and oxidation resistance similar to the parent metal.
