On Grain Boundary Engineering of UFG Metals and Alloys for Enhancing their Properties

The concept of grain boundary (GB) engineering of ultrafine-grained (UFG) metals and alloys is proposed for enhancement of properties by tailoring different GBs (low angle and high angle ones, special and random, equilibrium and non-equilibrium) and formation of GB segregations and precipitations using SPD processing. By variations of regimes and routes of SPD processing we show for several light alloys (Al and Ti) the ability to produce UFG materials with different grain boundaries, and this can have a dramatical effect on mechanical behavior of the processed materials. This paper demonstrates also several new examples of this approach for attaining superior strength and ductility as well as enhanced superplasticity at low temperatures and high strain rates in various UFG metals and alloys.