《《Long Term Thermal Stability of INCONEL Alloys 718》.pdf

LONG TERM THERMAL STABILITY OF INCONEL ALLOYS 718, 706, 909, AND WASPALOY AT 593ºC AND 704ºC Sarwan Mannan, Shailesh Patel, and John deBarbadillo Special Metals Corporation, 3200 Riverside Drive, Huntington, WV 25705 Abstract temperature strength whilst 909 was the poorest and retained only 50% of its strength. On 704ºC exposure, alloy This paper presents a study of the isothermal stability of 706 and WASPALOY retained their room temperature INCONEL* alloys 718, 706, 909, and WASPALOY**. impact strength better than alloy 718. The tested materials Standard annealed and aged materials were exposed at were subjected to optical microscopy to develop an 593ºC up to 10,000h and at 704ºC up to 5,000h. The understanding of the reasons for the above results. exposed materials were tested for room temperature tensile, room temperature impact, and high temperature tensile. The * INCONEL is a trademark of the Special Metals Family of strength of alloy 909 degraded on 593ºC exposure but 706 Companies and 718 retained their strength. At 704ºC exposure, ** WASPALOY is a trademark of the United Technology WASPALOY had the best stability in terms of high Corporation Introduction detected in γ′/ γ′΄ precipitates [7]. Since the effect of various elements on coherency strain at different atomic levels is Materials used in gas