Comparison of equal channel angular pressing and cold rolling in the evolution of microstructure and texture in zirconium

Abstract

Evolution characteristics of the microstructure and texture of severely deformed commercial purity Zr702 were studied. The mode of the severe deformation was either heavy cold rolling or equal channel angular (ECA) pressing. Equiaxed grains, present prior to the deformation, became elongated during deformation along the rolling direction or along the maximum shear direction for the case of cold rolling or that of ECA pressing, respectively. ECA pressing transformed the initial fiber texture to a quite different component, which was also the case for cold rolling. In both cases, the maximum intensity of texture increased with the amount of deformation. Complete recrystallization was realized upon subsequent heat treatment lasting 100 min. at 600°C, and the evolution characteristics of texture and microstructure were also similar for both modes of deformation. These similarities in the microstructure and texture were attributed to the particular route of ECA pressing employed in the present study, i.e., route A. It is therefore concluded that the deformation and annealing behaviors in this particular route of ECA pressing are essentially very close to those of cold rolling.

Low-temperature superplasticity of ultra-fine-grained Ti-6Al-4V processed by equal-channel angular pressing

“…[6,7] In this regard, previous investigations have shown that microstructure evolution is dominated by an increase in the fraction of high-angle grain boundaries (HAGBs) rather than grain refinement per se as the strain is increased above a value of ϳ3, i.e., the grain size is not decreased further at high strains. [4,36,37] Such an increase in HAGBs during SPD may lead to an increase in the GBS rate, resulting in higher values of m and, hence, higher total elongations. Nonetheless, the scaleup potential of ECAP is certainly greater than that of HPT, provided the production challenges associated with the requirement for low-strain-rate isothermal ECAP of Ti-6Al-4V can be met.…”

Texture and Twinning Evolution of Cold-Rolled Industrial Pure Zirconium

“…After the cold rolling process, the influence of slip did not alter the bimodal distribution of the texture; it merely transformed the < 11 -20 >//RD texture into the < 10 -10 >//RD texture. Zirconium alloy, with its a typical close-packed hexagonal structure and its texture after cold rolling deformation is not only affected by the availability of slip, but also by the twin deformation mechanism, which plays an important role [33].…”

Mechanisms of Sticking Phenomenon Occurring during Hot Rolling of Two Ferritic Stainless Steels

“…[1] Especially during hot rolling of stainless steels, the sticking usually appears at rear parts of roughening rolls or at front parts of finishing rolls, and leaves various defects such as dents or scratches on surfaces. [2][3][4][5][6] This also induces problems of reduction in roll life and hot-rolling productivity, and seriously deteriorates the surface quality of rolled products. At hot-rolling plants, instead of coming up with fundamental solutions to this sticking problem, it is generally addressed by making adjustments in hotrolling conditions according to rolling plans, for instance, by controlling the kind of lubricants or the spraying amount used to reduce the friction coefficient between rolls and rolled plates.…”