NOTCH SENSITIVITY OF AIRCRAFT STRUCTURAL AND ENGINE ALLOYS PART I. PRELIMINARY STUDIES WITH A-286 AND 17-7 PH (TH 1050) ALLOYS

摘要

This program was designed to extend previous analyses of the creep-rupture behavior of notched test specimens held under steady axial load. Experimental studies have also been planned and carried out in an effort to clarify the factors controlling rupture life in the presence of uniform complex stress.nVacuum melted-A-286 alloy produced by the consumable electrode process was chosen for this investigation with the expectation that a range of notch sensitivity could be developed by increasing the temperature of solution treatment. Extensive tests had been planned to study changes in smooth-bar properties corresponding to marked differences in notched-bar strength, in hopes of isolating all the major factors associated with notch sensitivity. For solution temperatures ranging from 1650°to 2300℉, the lot of material studied exhibited strong notch strengthening at 1200℉ for nearly all specimens tested with Kt's of 1.8, 3.0 and 4.1, despite elongation at fracture as low as 1% or less for certain solution temperature near 2200℉.