Reversible deformation in metals at elevated temperatures

摘要

At elevated temperatures elastic limits become increasingly difficult to define and, in conditions relevant to fatigue, where stresses may vary in amplitude and frequency, appropriate laws of deformation are difficult to establish. Data have been obtained through the construction and use of equipment permitting the measurement of the time dependence of strains down to 10{sup}-7 that follow small stress changes at elevated temperatures. The factors influencing primary creep and anelastic strain recovery have been determined and compared. Whilst the former showed a power law dependence and the latter a logarithmic dependence on time, their initial strain rates were similar on application and removal of a given stress. Reversible dislocation bowing through pipe diffusion is considered to contribute to such behaviour, though these initial strain rates were faster than those expected by this mechanism alone.