JBK-75 superalloy in solution annealed, with no aging, is negligibly embrittled by hydrogen at 34.5 MPa (5 ksi) pressure. Heat treatment study has shown that aging conditions would dramatically increase the US and UTS for JBK-75. However, such aging conditions would make JBK-75, including A-286 and

Because Inconel 718 has been used extensively for aerospace applications, detailed heat treatment studies were conducted by Walter and Chandler (ref. 16, 23) for rocket engine applications in a high pressure hydrogen environment. Table 17.8 presents the results of HEE Index for Inconel 718 in combin