Thermal stability of inconel alloy 783 at 593°C and 704°C

Abstract

INCONEL* alloy 783 is a low co-efficient of thermal expansion (CTE) superalloy. It is designed for high strength, good oxidation resistance, and higher temperature capability as compared to 900-series alloys. In this study, commercially produced alloy 783 was isothermally exposed at 593°C for up to 12,000h and at 704°C for up to 4,000h. This was followed by high temperature tensile testing and microstructural analysis. INCOLOY* alloy 909 was also isothermally exposed and tested under similar conditions to compare thermal stability. Isothermal exposure at 593°C resulted in significant decrease in strength for alloy 909, whereas the strength of alloy 783 was unaffected with this exposure. High temperature elongation of alloy 783 degraded to mid-teens with the initial l,000h exposure at 593°C and thereafter remained essentially constant for up to 12,000h exposure. On 704°C exposure, both the alloys lost significant strength, however, the loss of strength was more pronounced for alloy 909.