Monotonic and cyclic stress-strain behavior and strain-life resistance of USS-T1 are reported. The material exhibits a minimum monotonic yield strength of 105 ksi but, due to strain softening, develops a cyclic yield strength of 78 ksi. Initial precycling of fatigue specimens has little effect on their life when compared to non-precycled results. However, periodic incremental overstraining of specimens which did not fail in approximately 107 reversals reduces life by a factor of about 10.
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