Effect Of Intermediate Annealing Research Articles

Optimization in strength-ductility of Mg-Gd-Y-Zn-Zr alloy processed by upsetting-extrusion combined with intermediate thermo-mechanical treatment (ITMT)

In this work, the effects of intermediate annealing and intermediate annealing subsequent aging treatment on the second phase precipitation, dynamic recrystallization (DRX) behavior, and mechanical properties of Mg-9Gd-4Y–2Zn-0.5Zr (wt.%) alloy were comparatively studied. The results showed that the one-pass upsetting-extrusion (UE) deformation intermediate annealing treatment sample (UAE) exhibited the highest dynamic recrystallized (DRXed) grains number fraction and the largest average DRXed grain size, which was mainly attributed to the precipitation of a large number of β-Mg5RE phases (>1 μm) at the grain boundaries (GBs) and within unDRXed grains after annealing treatment. These β-Mg5RE phases promoted DRX through particle-stimulated nucleation (PSN) mechanism during subsequent extrusion process. However, the lack of the pinning effect of the fine second phase precipitations led to the growth of DRXed grains. The DRXed grains of the deformation intermediate annealing subsequent peak-aging treatment sample (UAAE) were significantly smaller than the UAE sample. This is mainly due to the fact that the densely distributed prismatic β′ phases precipitated by the peak-aging treatment were rapidly transformed into nano-scale β-Mg5RE phases and pinned at the DRXed grain boundaries to inhibit the growth of the DRXed grains during the subsequent extrusion process. The ultimate tensile strength (UTS) and failure elongation (EL) of the UAAE sample were 274 MPa and 14.3%, respectively, 4.2% and 85.7% higher than those of the UE sample, showing excellent strength-ductility synergy. The randomly oriented fine DRXed grains, coarse unDRXed grains with high-density dislocations and substructures, and nano-scale β-Mg5RE particles were co-contribute to the strength-ductility synergy.

Effect of intermediate annealing on microstructure and mechanical property of a Fe−19Mn−0.6C TWIP steel

Annealing is an effective strategy to improve the properties of high-strength twin-induced plasticity (TWIP) steels, however, the adaption of intermediate annealing during cold rolling (CR) is scarcely studied. Here, the Fe-19Mn-0.6C TWIP steel was subjected to CR-annealing and CR-intermediate annealing-CR-annealing processes at room temperature to determine the role of intermediate annealing in the improvement of microstructure and mechanical properties. The total cold-rolled reduction in both processes is 75%. The morphological and phase characterizations of the TWIP steel annealed for 1 h showed that uneven element distribution had occurred as the annealing temperature was greater than the recrystallization start temperature, causing the presence of minor carbides. Moreover, the carbides vanished at the recrystallization end temperature and were quantitatively analyzed content via the refined XRD. Finally, the recrystallized austenite grains completely replaced the cold-deformed microstructures. At the same total CR reduction of 75%, the TWIP steel exerted intermediate annealing facilitates the formation of twins, endowing the tensile strength vast increase. This would provide a significant reference to improve the mechanical properties of steels via annealing.

Effect of intermediate annealing and reduction ratio on the texture evolution and formability in AA5083

In the present study, the effect that intermediate annealing (IA) and reduction ratio (RR) exert on the microstructure and texture evolution in AA5083 sheets was investigated. The initial hot-rolled AA5083 sheet was subjected to the following thermomechanical process: primary cold rolling (CR-1) → intermediate annealing (IA) → secondary cold rolling (CR-2) → final annealing (FA). A reference (Ref) specimen was subjected only to CR-1 → CR-2 → FA with no IA process. Through-thickness microstructural heterogeneities were observed in the initial hot-rolled AA5083 sheet, and these features persisted in the CR-1 and IA specimens. The CR-2 and FA specimens, however, showed no through-thickness heterogeneities. Cold rolling enhanced the plane-strain texture components (Copper, Brass and S) whereas annealing enhanced the recrystallization texture components (Cube and ND-Rotated-Cube (RC)). Following FA, the non-IA (Ref) specimen showed a larger fraction of Cube and ND-RC components by comparison with specimens that had undergone IA. When the r-values predicted using the visco-plastic self-consistent (VPSC) model were compared with the experimental results, the r-value for the non-IA (Ref) specimen was smaller than those for the IA specimens after FA. The average r-value increased gradually (in a 45° direction) as the RR of CR-2 was decreased (70–40%). Controlling the RR of the CR-2 after IA resulted in isotropic sheets with enhanced formability. The largest r-value was observed in FA specimens with a small RR during CR-2. A balance between retaining deformation texture and the evolvement of the Cube component was responsible for the larger r-value.

Effect of Intermediate Annealing and Reduction Ratio on the Texture Evolution and Formability in Aa5083

Effect of Intermediate Annealing and Reduction Ratio on the Texture Evolution and Formability in Aa5083

Effects of intermediate annealing on the microstructure and transport properties of Bi-2223 wires and tapes

Monofilament and 37-filamentary Bi-2223 tapes were fabricated by powder in tube (PIT) process. And the mono-filamentary wires were drawn from ϕ12mm to hexagon 1.51 mm with one and three times intermediate annealing, respectively. The influences of different intermediate annealing times on the core density, morphology and transport properties of Bi-2223 wires and tapes were systematically investigated. It was noticed that the density and the Vickers micro-hardness values of superconducting core on the cross-section of one time annealing wires were higher than those of three times annealing wires. Meanwhile, it was observed that the Ag/oxide core interfaces of the wire with one time annealing were more smooth than those of the three times annealing wire. With the intermediate annealing time decreasing from three to one, the critical current density Jc increased from 17.9 kA/cm2 to 20.5 kA/cm2. And the enhancement of Jc-B properties suggests the improvement of intergrain connections due to the increasing core density. Meanwhile one time annealing procedure was used to Ag-Au sheathed tape, Jc reached 16.3 kA/cm2, this value was also higher than those traditional wires in our previous experiments, which suggests that the decreasing of annealing times during drawing process is also effective in AgAu sheath tapes for the enhancement of current capacity.

Effects of intermediate annealing on twin evolution in twin-structured Mg-Nd alloys

In the present study, in-situ electron back-scattered diffraction analysis was carried out to systematically investigate dominant mechanism for twinning process during re-compression after intermediate annealing in Mg alloys containing 0.03 at% and 0.18% at% Nd. The results show that twin growth is the dominant mechanism for both alloys during re-compression after annealing, while twin nucleation is the dominant mechanism for both alloys without annealing. Furthermore, the contribution of nucleation to twinning process decreases with the increase of Nd concentration for the alloys without annealing, while the contribution of nucleation increases with the increase of Nd concentration after annealing.

Effect of Intermediate Annealing on the Structure, Phase Composition and Properties of Cold-Rolled Foil from Hydrogen-Alloyed Alloy VT22I Under Aging

The methods of electron microscopy, x-ray diffraction, and measurement of microhardness are used to study the effect of intermediate annealing on the structure and properties of cold-rolled foil from hydrogen-alloyed alloy VT22I under aging at 350 – 500°C. It is shown that growth in the hydrogen content causes deceleration of the processes of decomposition of the β-phase under aging. Amode of thermomechanical treatment is suggested for fabricating foils from alloy VT22I with 0.25 wt.% H. The treatment includes cold rolling with intermediate annealing at 650 – 700°C and final aging at 450°C for 8 h and provides a high microhardness (about 6400 MPa).

Microstructural and textural evolutions of TZ410 alloy under various rolling conditions

The microstructure and texture component of plastic deformed metal and alloys show remarkable effects on properties and processing technique. In this work, the microstructural and textural evolutions of Ti51.9Zr34.6Al10V3.5 alloy (at.%) under various rolling treatments were investigated. XRD and TEM results showed that the phase constitution of all heavy-rolled specimens are α″ martensite and β phase. In addition, the fraction of martensite increased with rolling reduction. Crystal orientation analysis showed that the orientation of hot-rolled specimen was dispersed. After cold rolling, crystals in specimens showed obvious preferred orientation, and aggregation degree increased with rolling reduction. However, preferred orientation in various cold-rolled specimens was different. The major texture component changed from {111}〈112〉 for 60% cold rolled specimen to {111}〈110〉 for 80% thickness reduction. Furthermore, the effects of intermediate annealing on microstructure and texture were also investigated. Results showed that the intermediate solution treatment weakened the rolling effects on microstructural and textural evolutions. The mechanism of microstructural and textural evolution was also discussed. Our findings can further elucidate the microstructural evolution theory of metal and alloys and can serve as a basis for adjusting and controlling the microstructure and properties of TiZr-based alloys with high performance.

Effect of intermediate annealing on the microstructure and mechanical property of ZK60 magnesium alloy produced by twin roll casting and hot rolling

Twin roll cast (designated as TRC in short) ZK60 magnesium alloy strip with 3.5mm thickness was used in this paper. The TRC ZK60 strip was multi-pass rolled at different temperatures, intermediate annealing heat treatment was performed when the thickness of the strip changed from 3.5mm to 1mm, and then continued to be rolled until the thickness reached to 0.5mm. The effect of intermediate annealing during rolling process on microstructure, texture and room temperature mechanical properties of TRC ZK60 strip was studied by using OM, TEM, XRD and electronic universal testing machine. The introduction of intermediate annealing can contribute to recrystallization in the ZK60 sheet which was greatly deformed, and help to reduce the stress concentration generated in the rolling process. Microstructure uniformity and mechanical properties of the ZK60 alloy sheet were also improved; in particular, the room temperature elongation was greatly improved. When the TRC ZK60 strip was rolled at 300°C and 350°C, the room temperature elongation of the rolled sheet with 0.5mm thickness which was intermediate annealed during the rolling process was increased by 95% and 72% than that of no intermediate annealing, respectively.

The dependence of final microstructure, texture evolution and mechanical properties of Al–Mg–Si–Cu alloy sheets on the intermediate annealing

Effect of intermediate annealing on the microstructure, texture and mechanical properties of Al–Mg–Si–Cu alloy sheet in the different conditions was investigated by means of tensile test, microstructure characterization and texture measurement in this study. The results show that, three different intermediate annealing treatments (no annealing, low temperature annealing, high temperature annealing) have a great influence on the evolution of microstructure and texture, and final mechanical properties. Compared with the high temperature annealing and no intermediate annealing, the low temperature annealing is most beneficial to improve mechanical properties, especially for improving the average Lankford coefficient r and reducing Δr values, and to form the uniform recrystallization structure and the finer recrystallization grains. Although the intermediate annealing temperature only affects the intensities of textures formed by annealing treatments, and the intensities of β fibers formed by the following cold rolling, yet, the texture components are quite different in the three alloy sheets in the T4P state, and only the CubeND orientation produced by PSN effect appears in the alloy sheet treated by the low temperature annealing. Additionally, the relationship between texture, r value and yield strength was analyzed by VPSC model and slip theory in this paper.

The effect of intermediate annealing between cold rolled steps on crystallographic texture and magnetic properties of Fe–2.6% Si

The crystallographic textures and magnetic properties of Fe–2.6wt% Si after two different cold rolling and thermal treatment processes were investigated. The first set of samples was 90% cold rolled and annealed for 20min at 600°C, 700°C, 900°C and 1100°C, while the second set was cold rolled for 75% and 60% with intermediate annealing at 600°C for 60min. Samples were analyzed by neutron diffraction and magnetic measurements. By means of the one and two stage cold rolling processes important cube (001)[100] and Goss components {110}〈001〉 were produced. Magnetic properties obtained through the two stage process were better than the properties found with the one stage process due to a higher fraction of the cube and Goss components in the material after the two stage process. An increase of grain sizes does not lead to better magnetic properties.

Influence of intermediate annealing on the microstructure and texture of Ni-9.3at%W substrates

The effects of intermediate annealing (IA) on the microstructure and texture of Ni-9.3at%W substrates have been investigated by using electron backscattering diffraction and X-ray diffraction. Results suggest that IA can optimize the homogeneity of deformation microstructure. Higher IA temperatures (without undergoing recrystallization during IA) will increase the copper-type components of deformation texture and improve the content of cube texture after recrystallization. Sharp cube texture (97.2%) can be obtained at the optimum IA temperature of 650°C. The mechanism underlying the transition of deformation texture can be interpreted as that IA increases the dislocation slipping ability and suppresses the twinning deformation of Copper orientation in the subsequent rolling process. The observed strengthening of cube texture as a result of IA treatment is presumably attributed to the reduction of noncube nucleation and the optimization of preferential growth surrounding the cube nuclei.

Effects of Intermediate Annealing and Cold-rolling on Recrystallization Texture in 1050 Aluminum

Changes in microstructures due to cold-rolling and annealing were observed with SEM-EBSD system. The material used was a commercial 1050 aluminum with 10mm thickness. After solution heat treatment, specimens were cold-rolled at 83% followed by intermediate annealing at 773K for 10 s. Specimens for secondary cold-rolling were cut from the primary cold-rolled sheet, and then cold-rolled again at 83% followed by final annealing at 773K. Surface texture was formed after both the primary and secondary cold-rolling. Microstructures after the intermediate annealing and after the final annealing resembled one another, which composed of the surface texture components. Orientation splitting into the texture components was caused in each grain by cold-rolling. The recrystallized grains were formed as a result of growth of dislocation cells having orientations of the texture components, which lead to form the recrystallized microstructure with the surface texture.

Effect of Intermediate Annealing on the Structural, Electrical and Dielectric Properties of Zinc Ferrite: An XANES Investigation

Effect of Intermediate Annealing on the Structural, Electrical and Dielectric Properties of Zinc Ferrite: An XANES Investigation

Effect of intermediate annealing on the resistivity and strength of wire from low-alloy aluminum alloys of the Al–Zr–Fe–Si system

The effect of regimes of deformation-heat treatment on the resistivity (ρ) and strength (σr ) of wires from low-alloy aluminum alloys of the Al – Zr – Fe – Si system is studied. The Thermo-Calc software is used to compute the phase composition of the alloys.

Влияние промежуточного отжига на микроструктуру и микротвёрдость сплава Х20Н80 после интенсивной пластической деформации

The effect of intermediate annealing during severe plastic deformation on evolution nanocrystalline structure and mi-crohardness of Ni-Cr alloy. It is shown that the microhardness saturates at strain correspondent to ten whole revolutions. Intermediate annealing nickel chromium alloy subjected to 5 revo-lution and consequent HPT for 10 revolution leads to increase of saturation level comparing to HPT Ni-Cr alloy strained for 15 whole revolutions microhardness increases above the saturation value. This result is apparently due to the increase in the length of equilibrium grain boundaries after annealing, which contribute to defect formation kinetics during subsequent deformation.

Improving Brazeability of AA3003+Zn Brazing Aluminum Sheets by Final Annealing

Effect of intermediate annealing and final annealing on microstructures and properties of Al3003+Zn sheets is studied. The microstructure of aluminum sheets is observed by Optical Microscope and Transmission Electron Microscope，and the sagging resistance of aluminum sheets is tested by sagging test rig. The results indicate that complete recrystallization can be obtained after intermediate annealing at 380°C，and the recrystallization grain size of aluminum sheets reduces appreciably when annealing temperature rise. The sagging distance of aluminum sheets decreases proportionally with the grain size. Final annealing after final cold rolling eliminates subgrain structure of aluminum sheet, and improves sagging resistance of aluminum sheets observably.

Effects of cold rolling parameters on sagging behavior for three layer Al−Si/Al−Mn(Zn)/Al−Si brazing sheets

The effects of intermediate annealing (IA) and the final cold rolling (CR) condition on the microstructure and sagging resistance during brazing were investigated using three layer clad sheets composed of the Al−7.5 wt.%Si alloy (filler, thickness: 10 μm)/Al−1.3 wt.%Mn based alloy (core, 80 μm)/Al−7.5 wt.%Si alloy (filler, 10 μm). Also, the effect of 1.2≈2 wt.% Zn addition into the core on the sagging resistance of the clad sheets was determined. It was revealed that all the clad sheets fabricated by the optimum condition (IA at 690 K and CR to 20≈45%) show excellent sagging resistance with a limited erosion due to the formation of a coarsely recrystallized grain structure in the core during brazing. It was also revealed that the recrystallization behavior of the Al−1.3 wt.%Mn based alloy is hardly affected by the addition of 1.2≈2 wt.%Zn during the brazing cycle. Therefore, the sagging resistance of the clad sheets is found to be governed not by the Zn content added in the Al−1.3wt.%Mn based core, but by the intermediate annealing and final cold rolling condition.

Effect of intermediate annealing on texture, formability and ridging of 17%Cr ferritic stainless steel sheet

In order to improve the formability of ferritic stainless steel (FSS) sheets, the crystallographic texture of the sheets was modified by way of an intermediate annealing (IA) during the cold rolling. In the as-received hot band pronounced through-thickness texture gradients with a strong rotated cube orientation in the sheet center layer were observed. This strong initial texture has an impact on the texture and the resulting properties, including the undesired appearance of ridging, in the final recrystallized sheet. Instead of forming the {111}//ND γ-fiber texture typical of recrystallized low-carbon steel sheets, the recrystallization texture was notably shifted towards {334}〈4 8 ̄ 3〉. Introduction of an intermediate anneal during the cold rolling led to a weaker, more typical bcc rolling texture with less pronounced texture gradients. Accordingly, recrystallization gave rise to the characteristic γ-fiber texture. The evolution of the different rolling textures is interpreted by means of texture simulations based on the Taylor deformation theory. The recrystallization textures are explained in terms of a preferred nucleation of recrystallization at the preexisting grain boundaries and a subsequent growth selection. The improvement in sheet formability through the IA is demonstrated by means of analysis of the R-values. Ridging is assessed through surface profile measurements.

Effect of intermediate annealing on texture evolution and plastic anisotropy in an Al-Mg autobody alloy

The effect of intermediate annealing (IA) on texture evolution and plastic anisotropy of an Al-Mg autobody sheet was investigated. The formation of annealing textures after two kinds of final heat treatments was discussed with the aid of microstructural characterization. The results showed that the IA treatment had obvious influences on the final annealing texture as well as the resulting plastic anisotropy. It led to relatively lower recrystallization extent and stronger retained rolling orientations in the sheets after final heat treatment. The final annealing textures were very weak due to the dominant influence of particle stimulated nucleation. The other orientations occurring can either be attributed to genuine recrystallization or to recrystallization in situ. As a result of good suppression of the cube and rotated cube orientations, a good combination of normal anisotropy and planar anisotropy was achieved in the sample with IA and after O treatment.