Statistical and probabilistic modelling of uniaxial creep life of a Ti-6246 alloy

Repeat data on a Ti-6246 alloy at 773 K and 580 MPa provided a unique oppor tunity to identify stochastic creep properties and to use this information to build a probabilistic creep damage assessment for this alloy. The stocha stic nature of creep properties both under a single test condition (using a generalised gamma distribution) and under various test conditions (by comb ining this distribution with the Monkman-Grant relationship) were identifie d. Under the single test condition log failure times had a distribution ske wed to the right and log minimum creep rates had a distribution skewed to t he left. Over various test conditions a failure time distribution similar t o the Weibull distribution was most supported by the data. The observed log time to failure at 480 MPa was well within the extrapolated 95% confidence limits obtained from the Monkman-Grant model. Uncertainty about the exact distributional form increased this 95% confidence limit.