Influence of pressing temperature on microstructural development in equal-channel angular pressing

Grain Refinement in As-Cast 7475 Aluminum Alloy under Hot Equal-Channel Angular Pressing

“…an increasing of strength, 1,2) low temperature and/or high strain rate superplasticity [3][4][5][6] and thermal stability of such structures, 6,7) etc. Methods for the production of ultra-fine grained metals and alloys have been paid attention with important scientific and commercial interest.…”

“…Methods for the production of ultra-fine grained metals and alloys have been paid attention with important scientific and commercial interest. 1) For producing submicron-grained materials by imposing very large plastic strains, several techniques, including multiaxial forging, 8,9) accumulative roll-bonding 10) and equal-channel angular pressing (ECAP), [1][2][3][4][5][6][7] etc. are available at present time.…”

Influence of Processing Regimes on Fine-Grained Microstructure Development in an Al–Mg–Sc Alloy by Hot Equal-Channel Angular Pressing

“…The X-ray structural analysis was performed at the specimen surface areas with a diameter of ³1 mm by a photo method using the X-ray device URS-2.0. Specimens for SEM-EBSD and X-ray examinations were mechanically polished and then electropolished at 20 V in a solution of 30%HNO 3 and 70%CH 3 OH at a temperature of 243 K. The mean (sub)grain size was measured by the line-intercept method. In contrast, a bimodal grain structure containing partially coarse grains is evolved after 12 passes of ECAP at 573 K. One component of this structure comprises fine-grained bands aligned parallel to the pressing direction.…”

“…14,68) It has been shown that new grain formation can be delayed in such alloys, and relatively finer crystallites with more diffused dislocation subboundaries are evolved at much higher strains at low-to-moderate temperatures. 3,8) Besides, duplex microstructures containing unexpectedly coarse grains have been sometimes reported in some Alhigh Mg alloys during ECAP at high temperature. 4,6,7) All the above mentioned points emphasize that deformation temperature is one of the most complicated and the least understood parameters of ECAP.…”

“…On the other hand, it was found that the final grain size and the fraction of LABs evolved at high strains generally increase with increasing temperature in dilute and low-to-moderately alloyed aluminum alloys. 3,6,10,13) Such opposite effects of processing temperature on new grain formation are currently a matter of intense debate. The above picture becomes much more complicated in some highlyalloyed Al alloys, in which dynamic recovery is additionally inhibited by the presence of a large number of dispersoid particles and substitutional atoms in solid solution.…”