Unification of the most commonly used time–temperature creep parameters

Abstract

The determination of the time to rupture at low stresses and temperatures despite existing methods still remains a challenge. A new unifying time–temperature parameter is proposed. It represents a modification of the efficient, but numerically unstable Manson–Brown parameter. It incorporates the most commonly used time–temperature parameters such as Larson–Miller, Manson–Haferd and Orr–Sherby–Dorn as special cases for the calculation of the master curves. The procedure chooses the most appropriate master curve for the test data and calculates the corresponding coefficients. The inputs for the determination of the master curves are minimised to the least possible amount of test data. The proposed time–temperature parameter is included in a fast creep damage calculation procedure which is a part of a method for evaluating the total damage of the thermomechanically loaded components.