Estimating the equivalent strain in equal-channel angular pressing

An upper bound solution of ECAE process with outer curved corner

“…It is understood from this figure that the strain decreases with increasing both the die angle and the outer curved corner angle, and the effect of die angle is more pronounced than the effect of outer curved corner angle. Therefore, using dies with small angle but with large outer curved corner angle is beneficial because such a die configuration provides not only a large strain but also the possibility of extruding materials with low ductility [20][21][22][23].…”

A new method for estimating strain in equal channel angular extrusion

“…(4) for dies with outer curved corner. Inspections by Aida et al [29] showed that two Eqs. (3) and (4) give the same results at the upper and the lower bounds for the arc angle, ψ = φ − π and ψ = 0, respectively, and they differ by 5% under all other conditions for channel angles, φ, equal to 90 • and larger.…”

Factors influencing microstructural development in equal-channel angular pressing

“…It can be shown from first principles [26] that, for a die having Φ=90 o , the strain on each pass decreases slightly with increasing values of Ψ but, nevertheless, the strain for all values of Ψ is very close to ~1 [27]. Although several different procedures have been proposed for estimating the strain in ECAP, it can be shown that all of these procedures give consistent results [28] and, furthermore, these results are consistent also with model experiments including the pressing of layers of colored plasticine [29] or two half-billet samples bearing a rectangular grid on their inner surface [30]. Finally, it is important to note that experiments show an abrupt angle of Φ=90 o is more effective than less abrupt angles in the production of a homogeneous equiaxed microstructure in the as-pressed solids [31].…”