Room Temperature Rolling Research Articles

Effect of Cryogenic and Room-Temperature Rolling on the Microstructural Evolution and Mechanical Behavior of Spray-Formed 7055 Al-Zn-Mg-Cu Alloy

This study investigates the effects of room-temperature rolling (RTR) and cryogenic rolling (CR) on the microstructure, mechanical properties, and fracture morphology of spray-formed (SF) 7055 Al-Zn-Mg-Cu alloy, with a focus on the deformation across reductions ranging from 20% to 80%. Utilizing SF as the base processing technique, the study aims to overcome challenges associated with the alloy’s high content during conventional casting, such as segregation, grain coarsening, and the formation of internal defects. The findings indicate that CR significantly enhances the ductility and refines the microstructure of SF-7055 Al alloy compared to RTR, particularly at higher reductions. CR prevents the formation of severe cracks and maintains higher ductility and texture intensity, which are crucial for the demanding applications of this alloy in aerospace and transportation sectors. Microstructural analysis reveals that CR achieves a more uniform deformation, effectively reduces shear band formation, and facilitates the formation of finer and more evenly distributed precipitates due to suppressed solute atom mobility at cryogenic temperatures. Mechanical testing shows that CR enhances strength and hardness at lower reductions by maintaining high dislocation density, which does not annihilate as rapidly as in RTR. Tensile fracture analysis further demonstrates that CR leads to smoother fracture surfaces and fewer macroscopic cracks, indicating a more controlled failure mechanism. This study underscores the potential of cryogenic processing in improving the performance and applicability of high-strength Al alloys, offering significant insights for industrial applications where material reliability and enhanced mechanical properties are critical.

Enhanced Strengthening and Toughening of T6-Treated 7046 Aluminum Alloy through Severe Plastic Deformation

The 7046 aluminum alloy possesses a favorable fatigue property, corrosion resistance and weldability, but its moderate strength and plasticity limit its wider application and development. In the present study, severe plastic deformation (SPD) was applied prior to T6 treatment to significantly enhance the strength and toughness of the 7046 aluminum alloy. The results show that the alloy processed by four passes of equal channel angular pressing (ECAP) at 300 °C prior to T6 treatment exhibits an excellent mechanical performance, achieving an ultimate tensile strength (UTS) and elongation (EL) of 485 MPa and 19%, respectively, which are 18.6% and 375% higher than that of the T6 alloy. The mechanical properties of the alloy are further improved by an additional room temperature (RT) rolling process, resulting in a UTS of 508 MPa and EL of 23.4%, respectively. The increased presence of η′ and Al6Mn phases in the 300°C4P-R80%-T6 and 300°C4P-T6 alloys contributes to a strengthening and toughening enhancement in the SPD-processed T6 alloy. The findings from this work may shed new insights into enhancing the 7046 aluminum alloy.

Effect of room temperature rolling and annealing on microstructure and mechanical properties of (CrCoNi)96V4 medium entropy alloy

As cast (CrCoNi)96V4 medium entropy alloy（MEA）was prepared by vacuum arc melting. The MEA is deformed by rolling at room temperature with a total deformation of 67 %, The yield strength and tensile strength of the deformed MEA are 1297 MPa and 1410 MPa respectively, the elongation of the alloy is only 8 %.Then the deformed MEA was annealed for 30min at 700 °C, 800 °C and 900 °C respectively. The results show that the strength and ductility of the MEA after annealing were well balanced. The yield strength and tensile strength of the MEA after annealing at 900 °C/30 min are 678 MPa and 1024 MPa, and the elongation is maintained at 26 %. After annealing, a large number of annealing twins were formed in the MEA, which makes the strength and ductility of the MEA significantly improved. At the same time, Cr-rich particles were found in the MEA, which had positive effect on the improvement of the strength and ductility of the alloy.

Electrochemical Monitoring of Respiratory Infectious Disease on Nanostructured Surface Functionalized with Biosynthetic Multimer Aptamers

Multivalent aptamers have gained substantial interest owing to their enhanced affinity towards target analytes compared to their monomeric counterparts due to their capability to bind simultaneously to diverse regions of a target molecule, fostering more robust and enduring interactions. This study focuses on engineering the surface-based production and modification of multivalent aptamers through room temperature rolling circle amplification technique and chemically modified primers. This process starts with immobilizing modified primers onto an electrode to generate and arrange biosynthesised multivalent aptamers. These bio-engineered multivalent aptamers are utilized as bio-receptors for capturing a specific target (in this case, the SARS-CoV-2 spike protein). The entire surface amplification procedure is extensively characterized using electrochemical, microscopy, and spectroscopy methods, determining the optimal amplification duration for biosensing applications. Impressively, multivalent aptasensors shows substantially increased response signals and affinity compared to monomeric aptasensors. Moreover, the influence of surface structures on response signals is explored by employing both flat screen-printed gold electrodes and nano-/microisland (NMI) electrodes. NMIs-based multimeric aptasensors demonstrate notably heightened sensitivity in detecting SARS-CoV-2 spike protein within the range of 10 to 106 fg/mL in saliva and buffer media. Finally, the signal of the proposed aptasensor has been successfully assessed using several patient samples.

High-performance Al/Ti laminated composite via asymmetric cryorolling and its interface enhancement mechanism

The interface is crucial in determining the properties of laminated metal composites (LMCs). In this study, AA6061/TA1/AA6061 LMCs were produced via hot rolling and subsequent asymmetric cryorolling, followed by aging at 160 °C for 1.5 h. The mechanical properties of the materials were systematically investigated with regard to the impact of the interface during this process. The results demonstrated that the combination of asymmetric cryorolling and aging achieved superior mechanical properties of the composites, yielding a tensile strength of 397 MPa and a uniform elongation of 5.2 %, attributed to the introduced jagged interface and the reduction of interface voids, this procedure notably enhanced the bonding quality of the composites. The bonding strength was improved to 9.06 N/mm, 4.45 N/mm higher than the room temperature rolling + aged sample. Additionally, a more pronounced interface affected zone, approximately 64.7 µm, was noted in the subsequent deformation of the asymmetric cryorolling + aged sample, resulting in higher strain hardening capability. Furthermore, asymmetric cryorolling resulted in higher dislocation density, which maintained a high level even after aging. This phenomenon, along with the precipitated phase formed in the AA6061 layer, contributed to the enhanced strength.

Surface‐Based Multimeric Aptamer Generation and Bio‐Functionalization for Electrochemical Biosensing Applications

AbstractMultimeric aptamers have gained more attention than their monomeric counterparts due to providing more binding sites for target analytes, leading to increased affinity. This work attempted to engineer the surface‐based generation of multimeric aptamers by employing the room temperature rolling circle amplification (RCA) technique and chemically modified primers for developing a highly sensitive and selective electrochemical aptasensor. The multimeric aptamers, generated through surface RCA, are hybridized to modified spacer primers, facilitating the positioning of the aptamers in the proximity of sensing surfaces. These multimeric aptamers can be used as bio‐receptors for capturing specific targets. The surface amplification process was fully characterized, and the optimal amplification time for biosensing purposes was determined, using SARS‐CoV‐2 spike protein (SP). Interestingly, multimeric aptasensors produced considerably higher response signals and affinity (more than 10‐fold), as well as higher sensitivity (almost 4‐fold) compared to monomeric aptasensors. Furthermore, the impact of surface structures on the response signals was studied by utilizing both flat working electrodes (WEs) and nano‐/microislands (NMIs) WEs. The NMIs multimeric aptasensors showed significantly higher sensitivity in buffer and saliva media with the limit of detection less than 2 fg/ml. Finally, the developed NMIs multimeric aptasensors were clinically challenged with several saliva patient samples.

Surface-Based Multimeric Aptamer Generation and Bio-Functionalization for Electrochemical Biosensing Applications.

Multimeric aptamers have gained more attention than their monomeric counterparts due to providing more binding sites for target analytes, leading to increased affinity. This work attempted to engineer the surface-based generation of multimeric aptamers by employing the room temperature rolling circle amplification (RCA) technique and chemically modified primers for developing a highly sensitive and selective electrochemical aptasensor. The multimeric aptamers, generated through surface RCA, are hybridized to modified spacer primers, facilitating the positioning of the aptamers in the proximity of sensing surfaces. These multimeric aptamers can be used as bio-receptors for capturing specific targets. The surface amplification process was fully characterized, and the optimal amplification time for biosensing purposes was determined, using SARS-CoV-2 spike protein (SP). Interestingly, multimeric aptasensors produced considerably higher response signals and affinity (more than 10-fold), as well as higher sensitivity (almost 4-fold) compared to monomeric aptasensors. Furthermore, the impact of surface structures on the response signals was studied by utilizing both flat working electrodes (WEs) and nano-/microislands (NMIs) WEs. The NMIs multimeric aptasensors showed significantly higher sensitivity in buffer and saliva media with the limit of detection less than 2 fg/ml. Finally, the developed NMIs multimeric aptasensors were clinically challenged with several saliva patient samples.

Effects of Cryorolling, Room Temperature Rolling, and Aging Treatment on the Mechanical, Electrical, and Wear Properties of a Cu-6Ni-6Sn Alloy

Effects of Cryorolling, Room Temperature Rolling, and Aging Treatment on the Mechanical, Electrical, and Wear Properties of a Cu-6Ni-6Sn Alloy

Microstructure evolution, mechanical response, and corrosion resistance for a 2195 Al-Li alloy under different rolling reductions during cryorolling

This study used cryorolling (CR) and room temperature rolling (RTR) with different rolling reductions to process the 2195 aluminum-lithium alloy (Al-Li alloy, AA2195) sheets. Subsequently, the AA2195 sheets were artificially aged to the peak aging stage. Their mechanical properties, corrosion resistance, and microstructural evolution sheets were investigated using methods such as hardness testing, tensile testing, intergranular corrosion (IGC) experiments, electrochemical experiments, transmission electron microscopy (TEM), and electron probe microanalysis (EPMA). Compared to the RTR samples, the CR samples exhibited higher hardness, ultimate tensile strength, and elongation under the same rolling reduction conditions due to the combined effect of dislocation strengthening, grain boundary strengthening, and precipitation strengthening. The corrosion resistance of the RTR samples showed a declining trend with the increased rolling reduction. However, the corrosion potential of the CR samples exhibited a non-monotonic trend, first increasing and then decreasing, with the increased rolling reduction. The CR and RTR samples had similar microstructural evolution trends, leading to predominantly IGC morphologies in the IGC tests. The RTR and CR samples exhibited partial pitting morphologies at 70% rolling reduction, and the CR samples had more pronounced pitting characteristics than the RTR samples.

Unveiling the self-annealing phenomena and its effect on microstructure and texture evolution in the room temperature rolled Cu-0.13Sn-0.04Mg alloy

ABSTRACT In this study, we investigated the microstructural evolution of a Cu-0.13Sn-0.04Mg alloy that underwent heat treatment followed by room temperature rolling (RTR). Initially heat-treated specimens were rolled at room temperature (RT) with reduction ratios (RR) of 40% and 75% to perform microstructural and crystallographic textural analyses. Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were utilise to examine both initial and deformed microstructures. Both exhibited heterogeneous microstructural distributions. Shear bands (SBs) existed in the initial specimen and became main sites for the nucleation of new grains during heat treatment. A denser presence of SBs was noted in the RTR specimens. Remarkably, an unusual self-annealing phenomenon was observed in these specimens, culminating in the emergence of recrystallized grains at RT. A plethora of such grains was observed in the severely deformed specimens, with numerous nucleating grains appearing proximal to the SBs or deformed grain boundaries (GBs). Time dependent microstructure evolution was observed via ex-situ EBSD technique in the compressed specimens. Formation of new grains, increase in high angle grain boundaries (HAGBs), and dislocation annihilations were observed with the progress of time. The crystallographic texture evolution in the initial specimen was predominantly influenced by the S component. At lower strains, the fractions of Copper component increased, whereas at higher strains, a greater fraction of Brass and S components were induced. Following a 40% RR, a saturation in hardness value was observed, which could be potentially attributable to an accelerated rate of RT recrystallization in the case of 75% RR.

Good strength-ductility synergy achieved in a Fe62Ni16Co9Mn9Ti3Si1 Fe-high-entropy alloy with heterogeneous structures

Developing metal structural materials with a good combination of strength-ductility is of great significance for the rapid development of the aerospace industry and the energy industry. High-entropy alloys (HEAs) have attracted widespread attention due to their excellent mechanical properties, especially the excellent ductility and toughness of face-centered cubic (FCC) high-entropy alloys. However, similar to traditional alloys, there is a trade-off between strength and ductility in HEAs. In this paper, we report the successful preparation of Fe-HEA (Fe62Ni16Co9Mn9Ti3Si1 (atomic percentage, %)) with high strength-ductility synergy at room temperature by cryo-rolling and annealing at 600 °C for 10 min (CR600), which increases the yield strength by 59% compared to room temperature rolling (RR600), while the uniform elongation decreases by only 20%. The ultra-high yield strength and the not significant reduction in uniform elongation are mainly attributed to the formation of high-density dislocations, dual-phase bimodal ultra-fine grain heterostructures, (NiMn)3-xTix and (Fe, Ni)2SiTi composite nanoprecipitates, precipitation-induced chemical composition heterogeneity, and BCC→HCP phase transformation during tensile deformation during CR and subsequent annealing at a reduced temperature (600 °C). In addition, by increasing the annealing temperature of the alloy after CR to 800 °C, its uniform elongation can be increased to 53%, which is mainly due to the excellent strain hardening ability induced by changes in heterogeneous structures, nanoprecipitates, and martensitic phase transformation. Compared with other similar alloys, our CR alloy exhibits higher strength-ductility synergy. The results of this study provide a new perspective for developing HEAs with higher strength-ductility synergy.

Strengthening of duplex Mg–9Li–3Al–2Zn–1Sn alloy by solid solution and mixed rolling-induced second phase transition

This work investigated the microstructure and mechanical properties of Mg–9Li–3Al–2Zn–1Sn alloy after solid solution and mixed rolling (hot rolling followed by room-temperature rolling). The research results reveal that after solid solution, AlLi and Mg2LiZn3 phases disappear, while MgLi2Al phases partially disappear. The hardness of the β-Li phase is much higher than that α-Mg phase, and the strength of the alloy is significantly increased while the elongation decreases to 1.4 %. Low plasticity is mainly due to lattice distortion and the presence of coarse Sn-rich phases. After mixed rolling, a large quantity of second phase precipitation in the alloy plays a role of second phase strengthening. The Mg17Al12 phases are observed to precipitate inside the α-Mg phase, and the AlLi phases containing MgLi2Al and Mg2LiZn3 nanophases inside are found at the β-Li phase and α-Mg/β-Li phase interface. The YS and UTS of the mixed rolled alloy reach 253 MPa and 273 MPa, respectively, with an improved EL of 18.4 %.

Microstructure and Mechanical Properties of AA1050/AA6061 Laminated Composites Fabricated through Three-Cycle Accumulative Roll Bonding and Subsequent Cryorolling.

In this study, AA1050/AA6061 laminated composites were prepared by three-cycle accumulative roll bonding (ARB) and subsequent rolling. The effects of the rolling process on the microstructure evolution and mechanical properties of AA1050/AA6061 laminated composites were systematically investigated. The results indicate that the mechanical properties of the laminated composites can be effectively improved by cryorolling compared with room-temperature rolling. The microstructure analysis reveals that cryorolling can suppress the necking of the hard layer to obtain a flat lamellar structure. Moreover, the microstructure characterized by transmission electron microscopy shows that cryorolling can inhibit the dynamic recovery and significantly refine the grain size of the constituent layers. Meanwhile, the tensile fracture surface illustrates that AA1050/AA6061 laminated composites have the optimal interfacial bonding quality after cryorolling. Therefore, the laminated composites obtain excellent mechanical properties with the contribution of these factors.

Physical Simulation of Medium and Low Temperature Rolling of Mg-Li Alloy Sheet

In this paper, LZ91 magnesium-lithium alloy was taken as the research object. At the rolling temperature of room temperature and 453 K, the plane strain compression physical simulation experiment was carried out on the sample with one pass reduction of 15 % and three passes total reduction of 45 %. After each pass of rolling, the sample was annealed at 503 K for 30 min. Then the effects of different treatment processes on the microstructure of LZ91 magnesium-lithium alloy were studied by metallographic microscope, X-ray diffractometer and scanning electron microscope. The results show that under the same strain, the stress of room temperature rolling is larger than that of 453 K rolling; with the increase of annealing passes, the effect of work hardening gradually weakened. With the increase of rolling amount, the original mechanically mixed ' α ' phase and ' β ' phase will deform along the deformation direction, showing a streamline shape. Rolling at 453 K, the diffraction peak of the sample with 45 % total reduction of three passes changes the most.

Microstructure evolution and mechanical properties of Al/Mg–Li/Al laminate metallic composites via hot roll bonding and subsequent cryorolling

Hot roll (HR) bonded Al/Mg–Li laminated metallic composites (LMCs) were subsequent processed using room-temperature rolling (RTR) and cryorolling (CR), respectively. Afterward, the mechanical properties and the microstructure evolution of these LMCs under different rolling temperatures and reductions were studied. The results revealed that the Al/Mg–Li LMCs in the HR + CR1 group (a total reduction of 67 %) exhibited the best comprehensive mechanical properties, with the ultimate tensile strength and elongation ratio of 176.8 MPa and 10 %, respectively. The SEM and EBSD results revealed that the intermediate Mg–Li layer underwent an intense strain-induced phase transformation from the β-Li phase to the α-Mg phase during the RTR, while the strain-induced phase transformation during CR was inhibited due to the gradual atomic diffusion and insufficient driving energy. Therefore, the fraction of the β-Li phases in the Mg–Li layer was higher in HR + CR LMCs compared to HR + RTR LMCs, with the α-Mg phases in the former being evenly distributed in its β-Li matrix. Both β-Li and α-Mg phases in the Mg–Li layer held the stress and strain to ensure the ductility of the Mg–Li layer, which could consequently co-deform with the Al layers, thereby increasing the tensile strength and the elongation simultaneously in HR + CR LMCs. The XRD results revealed that during CR, multiple prismatic <a> slip systems and pyramidal <c+a> slip systems were activated in α-Mg phases, and the slip systems {110}<111>, {123}<111>, and {112}<111> were activated in β-Li phases simultaneously. The activation of a greater number of slip systems in both β-Li and α-Mg phases improved the overall ductility of the LMCs.

Self-Annealing Phenomena in the Cold-Rolled and Cryo-Rolled Copper Alloys: A Review

Severely deformed copper (Cu) alloys showed the self-annealing behaviour when exposed at room temperature (RT) for a prolonged time. This phenomenon results in the evolution of self-annealed grains, dislocations annihilations, and a decrease in the strength. The present review work addresses the evolution of self-annealed microstructures in room-temperature-rolled (RTR) and cryogenic-rolled (CR) Cu alloys, including various grades of Cu alloys such as ETP Cu, Cu-Fe-P, Cu-Sn-Mg alloys that were studied in terms of RT softening. Static recrystallization (SRX) at room temperature (RT) was observed in the highly deformed RTR and CR Cu alloy samples. Both discontinuous SRX (DSRX) and continuous SRX (CSRX) were responsible for the nucleation of small grains at RT. Particle-stimulated nucleation (PSN) also contributed to small-grain formations around Cu2O particles in ETP Cu. However, no PSN was reported for the Cu-Fe-P and Cu-Sn-Mg alloys. The formation of strain localizations (SLs) and shear bands (SBs) was observed in the deformed Cu alloys; these sites were preferred for grain nucleation during RT recrystallization.

Achieving ultrahigh specific strength of an ultrafine grained Mg–9Li–1Al alloy via the combined processing of ECAP with repeated annealing and rolling

A super-high strength Mg–9Li–1Al (LA91) alloy with ultimate tensile strength (UTS) of 312 MPa and specific strength of ∼215 kNmkg−1 was successfully achieved via a combined processing of multi-pass equal-channel angular pressing (ECAP) with repeated annealing and room temperature (RT) rolling. Significant grain refinement after ECAP led to the formation of ultrafine-grain (UFG) α-Mg phase with grain size of ∼350 nm. Further refinement of the α-Mg grains reaching ∼200 nm was achieved by further repeated annealing and RT-rolling with high dislocation density. The formation of strong basal texture of the α-Mg phase of the combined-processed alloy also contributed to the achieved excellent strength-ductility synergy. The 1 wt% Al (aluminum) in the Mg–Li dual-phase matrix acted as a high-efficient strengthening element, and was the major contributory factor to the 48% improved specific strength of the alloy compared to the UFG Mg–9Li binary alloy in our former study. The Al element distributing throughout the alloy phases without segregation contributed to the enhanced refinement of the α-Mg grains during the combined processing and improved strain-hardening rate during the tension plastic deformation, allowing for the achievement of a high strength of the LA91 alloy.

Deformation mechanism and mechanical properties of a CoCrFeNi high-entropy alloy via room-temperature rolling, cryorolling, and asymmetric cryorolling

The deformation mechanism and mechanical properties of CoCrFeNi high-entropy alloys (HEA) processed by room-temperature rolling (RTR), cryorolling (CR) and asymmetric cryorolling (ACR) were studied. As the rolling reduction increased from 20 % to 80 %, a transition in the dislocation and twinning deformation mechanisms occurred. The cryogenic environment in rolling process can promote the activation of the twins in the HEA at a lower strain, improving the deformation efficiency. The introduction of differential speed ratio led to the finer micro-shear bands with a more uniform distribution, so that the grains were refined to a greater extent. In the ACR HEA after large deformation, the stacking faults accumulated inside the deformation twins further refined the twins along the direction of long axis. This increased the strength of ACR HEA together with Lomer-Cottrell locks and FCC/HCP boundaries, reaching the maximum value compared with CR and RTR. The ultimate tensile strength exceeded 1450 MPa, and the yield strength of ACR HEA increased by nearly 1200 MPa compared to the initial material, while it still maintained the same elongation as RTR and CR. ACR showed the best strength-ductility combination during the whole rolling deformation process. The microstructure evolution and the strengthening contribution mechanism of different rolling were discussed and calculated, and the specific mechanism of how the introduced differential speed ratio further improves the strength-ductility synergistic strengthening in CR was clarified.

Effect of cryogenic rolling on the microstructure and texture of CuCrZr alloy

The evolution of microstructure and texture of CuCrZr sheet is studied during cryogenic rolling. It indicates that the grains of CuCrZr alloy rolled both at room temperature and at cryogenic temperature are elongated along the rolling direction. After annealing, the grains become equiaxed with a little smaller of cryogenic rolling than that of room temperature rolling. On the other hand, as the rolling reduction increases, the dislocation density increases with a feature of twinning deformation during deep cold rolling, which results of the texture of CuCrZr alloy during cryogenic rolling occurred mainly with composition of Goss {011}< 100 > texture and Brass {011}< 211 > texture accompanied by a strong Taylor {44 11}< 11 11 8 >and Copper {112}< 111 >textures. Meanwhile, R {124}< 211 > and S {123}< 634 > textures also appear on the section of φ2 = 65°. With the increase of processing reduction, twinning deformation is occurred, and Goss {011}< 100 > orientation continues to flow to Brass {011}< 211 > orientation, with no change in the strength of Copper and Taylor textures. However, the strength of R {124}< 211 > and S {123}< 634 > textures gradually increase, but the increase is smaller than the main Brass {011}< 211 > orientation so that the yield strength, tensile strength and uniform elongation of CuCrZr alloy sheet prepared by cryogenic rolling are higher than those of room temperature cold rolling at the same deformation conditions.

Improving Precipitation in Cryogenic Rolling 6016 Aluminum Alloys during Aging Treatment.

This study systematically investigated the performance and microstructure characterization of cryogenic rolling (CR) and room-temperature rolling (RTR) Al-Mg-Si alloys. The result showed that the hardness of the CR alloys decreased at the early aging stage, but that the hardness of the RTR alloys increased at the early aging stage. Retrogression phenomena were apparent in the CR alloys at the early aging stage. Despite undergoing the same solid solution treatment, a few substructures were still observed in the CR alloys, and the degree of recrystallization in the CR alloys was significantly inferior to that in the RTR alloys. After aging for 50 h, the strength and precipitates' density in the CR 75 alloy were higher than that in the other alloys; this indicated that the substructures were beneficial to precipitation and precipitate growth. A precipitation strength model was employed to illustrate the precipitation contribution at different aging stages. The results showed that the CR 75 alloy obtained the strongest precipitation strengthening.