Orowan strengthening with consideration of thermal activation

Abstract

Orowan strengthening is a key strengthening method for metallic materials. However, a debate still exists on the effect of temperature on the Orowan strengthening mechanism. Herein, the effect of temperature on the Orowan strengthening mechanism is systematically investigated, an Orowan strengthening mechanism with thermal activation is developed, and the corresponding Orowan stress is deduced. The results indicate that the precipitate scales substantially affect the thermal activation–based dislocation that bypasses the precipitate processes. In small precipitate scales, the thermal activation contribution to Orowan stress cannot be ignored; while in big precipitate scales, the thermal activation contribution can be ignored even at high temperatures. In addition to temperature, the effects of shear modulus, strain rate, and dislocation density on Orowan stress are investigated. This study not only provides new insight into the Orowan strengthening mechanism but also aids in designing new high-temperature structural materials.