Effect of one–pass strain on steady–state grain size by cyclic – HPT straining

The effect of one–pass strain, |±Δε|, on grain refinement was systematically investigated by cyclic – HPT straining with a repetitive deformation process in which positive and negative shear strain are introduced. The steady–state grain size, dss, depended on |±Δε| rather than the given total strain, Σ |±Δε|. The unstable dislocation cell walls formed by positive strain, +Δε, was discomposed by negative strain, −Δε. The stability of dislocation cell wall increased as the number of dislocations introduced by applying |±Δε| in a grain, n, increased. The decrease in n was caused by decreasing +Δε and grain size. It was found that n affected the stability of dislocation cell walls and was an important factor in determining dss © 2021 The Japan Institute of Metals and Materials