Alloy selection and alloy design both require consideration of an array of material attributes, including in-service properties, weldability, and fabricability. Critical properties of modern heat-resistant alloys for gas turbine applications include high-temperature strength, thermal stability, oxidation resistance, and fatigue resistance. In this paper, the properties of 12 solid-solution-strengthened and six age-hardenable heat-resistant alloys are compared. Weldability is an important attribute and can be a major limiting factor in the use of certain alloys. Weldability test methods are discussed, and the resistance of alloys to solidification cracking and strain-age cracking is compared. The use of weldability testing in the development of modern heat-resistant alloys is discussed with several examples cited. Finally, alloy selection for gas turbine components is outlined, taking into account both alloy properties and fabricability.

Issue Section:
Gas Turbines: Manufacturing, Materials & Metallurgy
Keywords:
aerospace industry, electricity supply industry, welding, thermal stability, oxidation, solidification, strain ageing, thermal resistance, gas turbines, alloys, materials testing
Topics:
Alloys, Fracture (Process), Heat, Cracking (Materials)
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 by American Society of Mechanical Engineers
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