Re-evaluation of tensile and creep rupture data of metals using a modified Larson–Miller approach

Abstract

More than 70 years ago, in 1952 Larson and Miller adapted an existing relationship which evaluates the relative effects of time and temperature on creep rupture behavior of various alloys by using existing data and by constructing so-called master curves. Since that time, the formulated Larson–Miller relation, commonly known as Larson–Miller parameter, is a widely used time–temperature parameter for various applications, e.g. for rupture life, creep and relaxation analyses of metals and some other materials such as polymers, concrete and ceramics. Nevertheless, the physical meaning of this parameter as well as the determination of master curves are still the subject of major criticism.

In this work, both aspects are reviewed and analyzed with data originally considered in the paper of Larson and Miller based on the following approach: (a) the parameter was modified regarding a reference time and a reference temperature according to the time–temperature superposition principle; (b) master curves were generated for five materials investigated originally by Larson and Miller, based on a stretched exponential function type.

It has been shown, that: (1) With normalized time and temperature, the Larson–Miller parameter corresponds to real logarithmic rupture time. (2) For the relationship between creep rupture stress and the modified Larson–Miller parameter, the stretched exponential function is a good choice as a master function. (3) Corresponding model parameters have physical meaning and can be easily determined based on data from creep test data. The investigations provide a better understanding and applicability of Larson–Miller approach.