Plastic strain localization in metals: origins and consequences

This article focuses on the mechanisms and consequences of plastic strain localizations exhibited in tensile stress–strain behaviors, fracture and fatigue. A broad overview is first presented, including important practical considerations and historical background; then dislocation mechanics based details are developed in subsequent sections. Material characterizations are portrayed beginning from the macroscopic and extending down to the critical nanoscale. Controlling influences of temperature, strain rate, grain size and deformation mode on strain localization are evaluated. Relations are established between otherwise apparently disparate variations in phenomena, materials, applied conditions, and size scales. Strengths and weaknesses of various model descriptions of material behaviors are discussed in light of experimental evidence and suggestions are put forward for further research into promising model approaches and for areas where new approaches appear to be needed. A paradigm is suggested for the development of improvements in understanding based on the needed evolution of ever-increasingly precise experimental results, accurate theoretical model descriptions and incorporation of this information into the rapidly progressing development of numerical/computer modelling of real material behaviors.