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Peak-aged AA6082 flat extrusions were cryorolled at liquid nitrogen temperature to three different thickness reductions, the reductions were 21%, 42% and 85%, respectively. Microstructure and plastic deformation behaviors of the initial as well as the rolled materials were studied by means of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and tensile tests at room temperature. The initial material showed fibrous grain structure. After cryorolling to 21% thickness reduction, grains in the alloy were obviously elongated and importantly, microband traces were detected in selected grains. More detailed information was obtained in the alloy after 42% thickness reduction. Here, numerous microbands aligned along slip planes with the highest resolved shear stress, producing fragmentation of grains, while rests of elongated grains were microband-free. A cryorolling strain of 85% has been found to be desirable for producing a hierarchical microstructure in the materials volume, featuring nano- and ultrafine grains with size <100 nm coexisted with micro-sized grains. The development of hierarchical microstructure could be considered as a consequence of the intersection between families of microbands. As a result, both the strength and uniform elongation of the severely cryorolled alloy, i.e. 85% thickness reduction, were more superior to other rolled alloys. Therefore, this study revealed that the single processing procedure, i.e., cryorolling, can be utilized to tailor for desired properties in favor of both strength and ductility for peak-aged AA6082 extrusions. [ABSTRACT FROM AUTHOR]

Al-Mg alloys with high Mg contents have attracted considerable interest given enhanced strength and simultaneously reduced density by high Mg solute concentrations. In the present study, we proposed a strategy of strengthening Al‐10wt%Mg binary alloy via heavy cryogenic rolling at liquid nitrogen temperature. Both cryogenic plastic deformation and a high concentration of Mg solute effectively suppress dynamic recovery during rolling, creating nanoscale and ultra-fine laminated grains containing a high density of dislocations in a nearly single-phase solid solution. The as-rolled Al‐10wt%Mg exhibits an average 0.2% offset tensile yield strength of 619 MPa, and average engineering and true ultimate tensile strengths of 689 and 726 MPa, accompanied by average uniform elongation of 5.3% exceeding the threshold value of 5% required for structural engineering applications. The high strength stems from enhanced solid-solution strengthening of a high concentration of Mg solute, significant grain boundary strengthening of nanoscale and ultra-fine laminated grains, and strong dislocation strengthening. The appreciable ductility can be primarily attributed to a high concentration of Mg solute that can retard dynamic recovery processes during tensile testing by impeding dislocation motion, thus enhancing dislocation accumulation and work-hardening ability. A high concentration of Mg solute combined with cryogenic plastic deformation to a high strain magnitude provides a new avenue to achieve ultrahigh strength and good ductility in non-age-hardened Al-Mg alloys. • High Mg containing Al-Mg alloy was processed by cryogenic rolling to high strain. • High Mg content, cryogenic temperature and high strain yield ultra-high strength. • A high concentration of Mg solute enhances dislocation storage and work-hardening. [ABSTRACT FROM AUTHOR]

Abstract: The deformation behavior of a soft particle containing Al–8Bi hypermonotectic alloy during equal-channel angular pressing was studied. The size, shape and distribution of soft Bi particles are substantially modified via shearing, fragmentation, coalescence and ripening. It is found that the soft Bi particles have a strong influence on promoting refinement of Al grains via particle stimulated continuous dynamic recrystallization. The present work provides an effective methodology to obtain monotectic aluminium alloys with well-dispersed soft phase particles. [Copyright &y& Elsevier]

Abstract: The microstructure and texture development of an extruded ZK60 Mg alloy during cyclic extrusion and compression (CEC) at 230°C was investigated. Tensile tests were performed at room temperature at a strain rate of 1×10−3 s−1. The results show that the microstructure was effectively refined by the CEC processing. The initial fiber texture became disintegrated during CEC processing and developed a new texture. After CEC 4-passes, the elongation-to-failure significantly increased almost three times compared with that of as-extruded alloy. Texture change and grain refinement were considered to be responsible for the large tensile ductility in the CEC processed ZK60 alloy. Furthermore, the smaller intensity of texture of CEC processed specimen may be another reason for the large ductility. [Copyright &y& Elsevier]

The effect of Zr and Er on the microstructure, electrical conductivity and mechanical properties of Al-0.4Fe alloy was investigated using optical microscope (OM), scanning electron microscope (SEM), electron back-scattered diffraction (EBSD), transmission electron microscope (TEM) and energy dispersive x-ray spectroscopy (EDS). It is revealed that both of the Zr and Er could inhibit the recrystallization process of Al-0.4 wt %Fe alloy due to the formation of Al 3 Zr or Al 3 Er particles. Zr is more recrystallization-resistant than Er due to the preferential precipitation of Al 3 Zr. Both of the Zr and Er could modify the morphology of Al 3 Fe particle from needle-like to sphere-like or rod-like, which reduce the negative effect of Al 3 Fe phase. Zr could significantly refine dendrites of the Al-0.4Fe alloy, while Er shows a negligible effect on dendrite refining due to the delayed formation of Al 3 Er during solidification. However, the low solubility of Er is beneficial for strength and electrical properties of Al-0.4Fe alloy. In consideration of strength and electrical conductivity, the Al-0.4Fe-0.2Er is selected as the best alloy among the four alloys, which shows a yield strength of 145 MPa, elongation at fracture of 8% and electrical conductivity of 61.2 %IACS after cold-rolling. The results provide an insight in design high strength, high conductive aluminum conductor material. • The coarse needle-like Al 3 Fe phases could be modified into sphere- and rod-like small particles by Zr and Er additions. • Synergetic improvement of strength and conductivity in Al-0.4Fe-0.2Er alloy is gained. • Co-adding Zr and Er improves recrystallization resistant capability of the Al-0.4Fe alloy better than the single one. [ABSTRACT FROM AUTHOR]

An Al-0.4Fe-0.15Zr-0.25Er alloy was processed by high pressure torsion (HPT) at room temperature in order to explore the evolution of property, microstructure and texture during HPT. The evolution of microstructure revealed by electron back-scattered diffraction (EBSD), transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). The microhardness increases with increasing strain up to 60 HV at a strain of about 12, and then decreases slightly to a steady stage. HPT processing leads to a significant increase (>100%) in microhardness at expense of a slight reduction (<3%) in electrical conductivity. The synchronous improvement in microhardness and electrical conductivity is obtained after aging. A significant decrease from 40 μm to 600 nm in grain size is observed after HPT deformation for 5 turns and beyond. HPT processing might accelerate the dissolution of the Al 3 (Zr,Er) precipitate. The A- {111} <110>and C- {001} <110> texture components are dominating after 0.25 turn. After 1 turn, the A and C components weaken, and the {112} <111> new component appears. The texture is weak and close to random due to recovery and recrystallization after 5 turns and beyond. • HPT processing leads to a significant increase in microhardness at expense of a slight reduction in electrical conductivity. The synchronous improvement in microhardness and conductivity is obtained after aging. • The grain size was significantly decreased from 40 μm to 600 nm by HPT. HPT might accelerate the dissolution of the Al 3 (Zr,Er) precipitate. [ABSTRACT FROM AUTHOR]