THERMAL STABILITY OF INCONEL ALLOY 783 AT 593°C AND 704°C

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 900series 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 1,000h 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.