Rolling Annealing Research Articles

Tailoring Texture to Highly Strengthen AZ31 Alloy Plate in the Thickness Direction via Pre-tension and Rolling–Annealing

Tailoring Texture to Highly Strengthen AZ31 Alloy Plate in the Thickness Direction via Pre-tension and Rolling–Annealing

Effects of Cold Rolling Annealing Process on Corrosion Resistance of Semi-process Electrical Steel of Middle and Low Grades

Semi-process non-oriented electrical steel with poor corrosion resistance is easily get rusted during the process of production, transportation, and application by end customers. In response to this problem, the paper studies the effect of different tapping temperatures in the cold rolling annealing process and cleaning process after tapping on its corrosion resistance. The results show that the higher the tapping temperature is, the worse the corrosion resistance will be. Cleaning with formic acid can increase its corrosion resistance.

Effect of cold rolling reduction on microstructure, mechanical properties, and texture of deep drawing dual-phase (DP) steel

In this study, the microstructure, mechanical properties, and texture of deep drawing dual-phase (DP) steel subjected to different cold rolling reductions were characterized via optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffraction (XRD) techniques. The results revealed that the microstructure of the steel is composed of ferrite and a small amount of martensite after cold rolling annealing. The ferrite grain size varied only slightly with the reduction. In addition, the orientation density along the γ orientation line increased continuously with increasing cold rolling reduction ratio. Similarly, the {112}〈110〉 and {223}〈110〉 components along the α orientation line and the adjacent {554}〈225〉 and {332}〈113〉 components were strongly developed. The ratio of the {111} plane texture volume fraction to that of the {100} plane texture, i.e., V{111}/V{100}, increased initially and then decreased, reaching the optimum value at 75% reduction. The maximum strength of the steel (i.e., 430 MPa) was realized at 55% reduction. However, the best elongation and r values (29.8% and 1.46, respectively) were obtained at 75% reduction.

Effect of cold rolling reduction on microstructure, mechanical properties, and texture of deep drawing dual-phase (DP) steel

In this study, the microstructure, mechanical properties, and texture of deep drawing dual-phase (DP) steel subjected to different cold rolling reductions were characterized via optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffraction (XRD) techniques. The results revealed that the microstructure of the steel is composed of ferrite and a small amount of martensite after cold rolling annealing. The ferrite grain size varied only slightly with the reduction. In addition, the orientation density along the γ orientation line increased continuously with increasing cold rolling reduction ratio. Similarly, the {112}〈110〉 and {223}〈110〉 components along the α orientation line and the adjacent {554}〈225〉 and {332}〈113〉 components were strongly developed. The ratio of the {111} plane texture volume fraction to that of the {100} plane texture, i.e., V{111}/V{100}, increased initially and then decreased, reaching the optimum value at 75% reduction. The maximum strength of the steel (i.e., 430 MPa) was realized at 55% reduction. However, the best elongation and r values (29.8% and 1.46, respectively) were obtained at 75% reduction.

Elevated temperature tensile tests on DU–10Mo rolled foils

Studies were completed to obtain tensile mechanical properties for uranium-10 wt.% molybdenum (U10Mo) foils which were subjected to four different thermomechanical processing conditions. UMo alloy foils are being investigated to support fuel conversion of high power research reactors from their current high enriched fuel form to a low enriched fuel form. Mechanical properties of the fuel foil have an effect on irradiation performance and fuel fabrication and therefore are required to support modeling and qualification of new low-enriched uranium monolithic fuel plate designs. The data contained in this document contributes to fuel qualification by fulfilling the requirement that physical properties related to fuel meat be established. It is expected that depleted uranium-10 wt% Mo (DU–10Mo) mechanical behavior is representative of the low-enriched U10Mo to be used in actual fuel plates; therefore DU–10Mo was studied to simplify material processing, handling, and testing requirements. In this report, the different thermomechanical treatments included variations of wrought hot and cold rolling reduction and post rolling annealing. Each of the four foils was hot rolled. After hot rolling reduction, three of the four foils were further reduced by cold rolling. One of the three was reduced a further 20% by cold rolling, and the remaining two were reduced 50% by cold rolling. Following cold rolling reduction, one of the two foils which had been reduced 50% by cold rolling was annealed at 650 °C. Performing this analysis allows assessment of the impact of foil fabrication history on the resultant tensile properties DU–10Mo fuel foils.Tensile properties of DU–10Mo at room temperature through approximately 400 °C determined from the tests conducted herein suggest the material is stronger and has lower ductility than what has been reported previously in the literature. The explanation for these differences has yet to be determined, but is likely related to differences in grain size and/or impurity content, and variation in fabrication history. At the highest temperatures tested (550 °C) better agreement between the values reported here and available literature was found. As expected, yield and ultimate tensile strength decreased with increasing test temperature. Generally, the yield stress for all foil processing conditions was found to be in the range of 1100 MPa for room temperature tests, and in the range of 200 MPa for tests conducted at 550 °C. Ultimate tensile stress was in the range of 1175 MPa at room temperature, decreasing to approximately 225 MPa at 550 °C. Elongation increased significantly, from 0 to 2% at room temperature to 50% or more for the tests at 550 °C.

High-performance lithium-ion batteries with 1.5 μm thin copper nanowire foil as a current collector

Abstract Cu Foil, a thin sheet of Cu, is the common anode current collector in commercial lithium ion batteries (LIBs) which accounts for ∼ 10 wt% of the total cell weight. However, thickness reduction of LIB-based Cu foils below 6 μm has been limited by the incapability of conventional rolling annealing or electrodeposition process. We here report a new type of Cu foil, so called Cu nanowire foil (CuNW foil), for use as an LIB anode current collector. We fabricate Cu NW foils by rolling press Cu nanowire fabric to reduce the thickness down to ∼1.5 μm with an areal weight down to ∼1.2 mg cm−2 and a density approximately 96% to that of bulk Cu. The rough surface and porous structure of CuNW foil enable better wetting and adhering properties of graphite slurry on foil. In full cell examination, a cell of a areal capacity of 3 mAh cm−2 exhibits 83.6% capacity retention for 600 cycles at 0.6 C that meets the standard specification of most commercial LIBs. As a proof-of-concept of demonstration, we fabricate a 700 mA pouch-type battery implemented with graphite-Cu NWs foil anodes to serve as energy supply to operate electronic devices.

Calculation of plastic strain ratio of AA1050 Al alloy sheet processed by heavy asymmetric rolling–annealing followed by light rolling–annealing

A study has been made of the texture evolution and the plastic strain ratios (the R-values) of AA1050 Al alloy sheets which were subjected to heavy asymmetric rolling–annealing followed by light rolling–annealing to improve the deep drawability of the Al alloy sheets. The heavily rolled Al alloy sheet evolved a shear texture consisting of {001}〈110〉 and ND//〈111〉. The R-values of the heavily rolled (90%) and annealed Al alloy sheets were measured and calculated from the measured sheet textures using the Bunge method. The calculated R-values were in good agreement with the measured data. A light rolling by 20% and annealing at 400°C following the heavy rolling–annealing decreased the rotate cube texture component, {001}〈110〉, of the sheet texture and in turn increased the ND//〈111〉 component and gave rise to the highest average R-value (R‾) and the lowest |ΔR| value. The calculated R‾ and |ΔR| values were in fairly good agreement with the measured data.

Microstructural evolution and shear strength of AuSn20/Ni single lap solder joints

AuSn20 (mass fraction) solder was prepared by laminate rolling–annealing method in an argon atmosphere. We investigated the interfacial reactions between the AuSn20 solder and the metalized Ni layer, and evaluated the effect of the interfacial reactions on the mechanical reliability of AuSn20/Ni joints with a long term solid-state aging by the single lap shear test. After the reflow process, fine eutectic structure and some hexagon (Ni,Au)3Sn2 phases were observed in the solder matrix. During the aging treatment, the microstructure of the joint was coarsening significantly. The effects of aging treatments on the structure of the joints were obtained: aging at 150°C for different aging time, the microstructure of AuSn20/Ni joints did not change much; after aging at 200°C for 300h, a thin (Au,Ni)Sn+(Ni,Au)3Sn2 multi-layer was formed at the interface; by prolonging the aging time to 500h, the (Au,Ni)Sn layer became thick with a distinct line above the (Ni,Au)3Sn2 layer; the total thickness of the intermetallic compounds (IMCs) layer grew with the increasing aging time. The as-reflowed joint had a higher single lap shear strength than the aged joints. All specimens fractured at the interface between the solder and IMC layer. The fracture surfaces demonstrate that the reduction in shear strength of the AuSn20/Ni joint was caused primarily by the coarsening of the microstructure.

Microstructure and mechanical property of cold rolled low carbon steel after prolonged annealing treatment

The effects of ferrite–pearlite and ferrite–martensite starting microstructures on ferrite grain sizes and carbide particle sizes after cold rolling and prolonged annealing treatment have been investigated. Ferrite–martensite starting microstructures showed finer grain and particle sizes and improved tensile properties after cold rolling annealing cycle compared to ferrite–pearlite starting microstructures. A ‘fibrous’ martensite morphology developed by intermediate quenching treatment is more beneficial in that respect compared to the ‘blocky’ martensite morphology obtained from the step quenching treatment.

Cu/single-walled carbon nanotube laminate composites fabricated by cold rolling andannealing

The remarkable mechanical, electrical and thermal properties of single-walled carbonnanotubes (SWCNTs) have attracted extensive research interest as structural andfunctional materials. In particular, SWCNTs have been used to reinforce polymers andceramic composites and great progress has been made. For metal matrix composites, thelimitation of the conventional manufacturing process and the difficulty in dispersingnanotubes within metal matrices hinder the development of metal matrix composites. Inthis paper, we demonstrate a successful fabrication of Cu/SWCNT laminate composites bycombined techniques of cold rolling and annealing, using 19 layers of large-area SWCNTfilms sandwiched between 20 layers of Cu thin foils. The tensile strength and Young’smodulus of the resultant laminate composites are 361 MPa and 132 GPa, respectively,exhibiting an improvement over the comparative pure Cu foils processed underidentical conditions. These results suggest that good interfacial adhesions betweennanotubes and the Cu matrix have been achieved after the rolling–annealing–rollingprocesses.

Properties of two-phase intermetallic (Ti, Nb) 3 (Al, Si) + (Ti, Nb) 5 (Si, Al) 3 P/M bulk and sheet material

Intermetallic Ti-based alloy powder with nominal composition Ti 23.5Al 5.5Si 10Nb (at.%) was produced by argon gas atomization. This dual phase alloy is composed of the α 2-(Ti, Nb) 3 (Al, Si)-matrix phase and a eutectic mixture of α 2-(Ti, Nb) 3(Al, Si) + ξ-(Ti, Nb) 5 (Si, Al) 3. The powder was compacted by hot isostatic pressing, subsequently hot rolled into sheets, and heat treated. The microstructures of the HIPed compacts and of the sheet materials were metallographically characterized and correlated with tensile properties at temperatures between 20 and 1000°C. Due to networks of the brittle ξ-silicide phase, the HIPed state showed no ductility at 20°C. Break-down of the silicide network during rolling led to an improved ductility at 20°C. After post rolling annealing, the yield strengths at 20 and 700°C were between 750-490 MPa and 700-420 MPa for specimens taken parallel and perpendicular to the rolling direction, respectively. These values are considerably higher than those reported for γ-TiAl sheets. At 1000°C the sheet material could be superplastically deformed.