Fatigue Testing of Forged Titanium

摘要

Results from fatigue testing with specimens of forged titanium AMS 4971 satisfying the Saab-Scania specifications 6466-2 and 6466-3 are presented. The specimens were taken longitudinally as well as transversely from six similar forgings. They were turned and either plain (k sub t = 1.0) or notched (k sub t = 2.5 and 4.0). The fatigue testing was carried out with r = -1, R = 0, and sigma min = 250 N/sq mm. Supplementary static tests were performed. The ultimate tensile strength for plain specimens was 1020 and 1230 N/sq mm for 6466-2 and 6966-3, respectively. Most of the fatigue testing was devoted to 6466-2 returning seven S-N curves. Comparisons between the two conditions (6466-2, 6466-3) and the two forging directions (longitudinal, transverse) were made in the case k sub t = 2.5/R = 0. No marked differences were noticed. Large scatter was noticed for 6466-2 in the case k sub t = 1.0/R = 0.