Overheating of Waspaloy: Effect of cooling rate on flow stress behavior

Abstract

During service of a gas turbine engine, components may suffer instant overheating which is a concern to safe operations. Effect of short overheating on the tensile properties of a Ni-based superalloy Waspaloy has been studied due to its significant importance for practical applications. The results have shown that a combination of near supersolvus overheating at 1000 °C with very rapid cooling at a rate of 50 K/s is most detrimental case to the tensile properties of the material. This is attributed to the absence of γ′ and carbide re-precipitation and growth during cooling period. Microstructure change during overheating and cooling has been deduced using in-situ resistivity measurements. This work provides evidence that multilateral measurements including resistivity can shed light on the failure controlling parameters.

Keywords

• Waspaloy
• Overheating
• Heat treatment
• Electro-thermal mechanical testing (ETMT) system
• Miniature tensile test
• Superalloy