scholarly journals Effects of Annealing and Deformation on Sagging Resistance of a Hot-Rolled, Four-Layered Al Alloy Clad Sheet

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Minglong Kang ◽  
Li Zhou ◽  
Yunlai Deng ◽  
Jinqin Lei
Keyword(s):  
Annealing Temperature ◽  
Reduction Rate ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Composite Sheet ◽  
Aluminum Composite ◽  
The Core ◽  
Clad Sheet ◽  
Lower Temperature ◽  
Hot Rolled

Multilayer brazeable aluminum alloy sheet is prone to collapse during high-temperature brazing process. The sagging resistance of the aluminum composite sheet needs to be further improved for quality control. Effects of annealing and rate of reduction on sagging resistance, microstructure, and Si diffusion of a hot-rolled, four-layered Al clad sheet (4343/3003/6111/3003) were investigated by means of a sagging device, OM, SEM, and TEM. Results showed that once annealed at 360°C, the sagging distance was increased from 3 to 15.7 mm as the reduction rate changed from 10% to 40%. By increasing annealing temperature to 410°C, those were changed from 3.1 to 20.8 mm accordingly. At 360°C/40% and 410°C/40%, specimens exhibited weak sagging resistance, whereas fine recrystallized grains were formed in the core promoting Si penetration along grain boundaries. While the specimens were treated at 360°C/10% and 410°C/10%, better sagging resistance was observed due to the formation of coarse recrystallized grains that can suppress erosion of Si. At the same reduction rate, the sagging resistance was higher for the sample annealed at a lower temperature as more precipitates appeared in the core (at 360°C), thus leading to an increase in strength.

Microstructural Changes with Annealing of a Nanostructured Al Alloy Severely Plastic Deformed by Four-Layer Stack Accumulative Roll-Bonding Process

2020 ◽  
Vol 20 (7) ◽  
pp. 4419-4422
Author(s):  
Seong-Hee Lee
Keyword(s):  
Aluminum Alloy ◽  
Annealing Temperature ◽  
Rolling Direction ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Heterogeneous Structure ◽  
Microstructural Changes ◽  
Ultrafine Grained ◽  
Coarse Grains ◽  
Ultrafine Grained Microstructure

Microstructural changes with annealing of a nanostructured complex aluminum alloy fabricated by 3 cycles of four-layer stack ARB process using different Al alloys were investigated in detail. The four-layer stack ARB process using AA1050, AA5052 and AA6061 alloy sheets was performed up to 3 cycles without a lubricant at room temperature. The sample fabricated by the ARB is a multi-layer aluminum alloy sheet in which the AA1050, AA5052 and AA6061 aluminum alloys are alternately stacked to each other. The layer thickness of each alloy became thinner and elongated to the rolling direction with the number of ARB cycles. The grain size decreased with increasing of the number of ARB cycles, and became about 160 nm in thickness after 3 cycles. The complex Al alloy still showed ultrafine grained microstructure to annealing temperature of 300 °C, but it had a heterogeneous structure containing both the ultrafine grains and the coarse grains due to an occurrence of discontinuous recrystallization after 350 °C.

scholarly journals An assessment of static recrystallization in L-605 Cobalt-based superalloy

10.30544/231 ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 221-236
Author(s):  
Padina Ajami Ghaleh Rashidi ◽  
Hossein Arabi ◽  
Seyed Mehdi Abbasi
Keyword(s):  
Cold Rolling ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Static Recrystallization ◽  
Microstructural Analysis ◽  
High Annealing ◽  
Microstructural Evaluation ◽  
Cold Rolled ◽  
Lower Temperature ◽  
Hot Rolled

In this research, the effect of cold rolling, annealing time and temperature on microstructure and hardness were studied in L-605 superalloy. A cast bar of L-605 alloy was hot rolled at 1200ºC. As the following, it was solutionized at 1230 ºC for 1 hour and finally was cold rolled by different amounts (i.e. 5-35 percent thickness reduction). The cold-rolled samples were heat treated for different times (i.e. 2-120 min.) at temperature range of 1068-1230 ºC in order to study their recrystallization behavior. The results of microstructural analysis indicated that static recrystallization is responsible for microstructural refinement and coarsening, so that an increase in the amounts of cold rolling resulted in a fully recrystallized microstructure at lower temperature. This analysis also indicated that annealing temperature is more effective than annealing time in grain growth. Microstructural evaluation as well as showed that carbides such as M7C3 and M23C6 which have been reported in some literature were not observed during rolling or annealing in this research. It is perhaps due to usage of high annealing temperatures or possibly due to their very low contents which was not possible for us to evaluate their formation with conventional methods. Hardness results revealed that higher annealing temperature lead to lower hardness values as expected.

Effects of Surface Strength and Temperature on Warm Forming of MG-AL-SUS Clad Sheet

2010 ◽  
Vol 443 ◽  
pp. 183-188
Author(s):  
Young Seon Lee ◽  
Taek Woo Jung ◽  
Dae Yong Kim ◽  
Young Hoon Moon
Keyword(s):  
Elevated Temperatures ◽  
Interface Strength ◽  
Alloy Sheet ◽  
Warm Forming ◽  
Mg Alloy ◽  
Uniaxial Tensile ◽  
Al Alloy ◽  
Essential Property ◽  
Drawing Ratio ◽  
Clad Sheet

Clad metal sheets are composed of one or more different materials joined by resistance seam welding, roll-bonding process, etc. Good formability is an essential property in order to deform a clad metal sheet to a part or component. Temperature is one of the major factors affected the interface strength and formability on warm forming of multilayered sheet metal. In this study, the mechanical properties and formability of a Mg-Al-SUS clad sheet are investigated. The clad sheet was deformed at elevated temperatures because of its poor formability at room temperature. Tensile tests were performed at various temperatures above 250°C and at various strain rates. The limit drawing ratio (LDR) was obtained using a deep drawing test to measure the formability of the clad sheet. Interface strength and fracture pattern were changed mainly by temperature. Uniaxial tensile strength represents entirely different type below and above 200°C at also different strain rate. Mg alloy sheet was fractured earlier more than SUS and Al alloy sheet below 250°C testing temperature. On the contrary, Mg alloy sheet was elongated much more than other metals above 250°C.

scholarly journals Microstructure and Mechanical Properties of Novel Quasibinary Al-Cu-Yb and Al-Cu-Gd Alloys

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 476
Author(s):  
Sayed Amer ◽  
Ruslan Barkov ◽  
Andrey Pozdniakov
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Mechanism Of Action ◽  
Annealing Temperature ◽  
Eutectic Reaction ◽  
Solidification Process ◽  
Annealed State ◽  
Microstructure And Mechanical Properties ◽  
Cold Rolled ◽  
Hot Rolled

Microstructure of Al-Cu-Yb and Al-Cu-Gd alloys at casting, hot-rolled -cold-rolled and annealed state were observed; the effect of annealing on the microstructure was studied, as were the mechanical properties and forming properties of the alloys, and the mechanism of action was explored. Analysis of the solidification process showed that the primary Al solidification is followed by the eutectic reaction. The second Al8Cu4Yb and Al8Cu4Gd phases play an important role as recrystallization inhibitor. The Al3Yb or (Al, Cu)17Yb2 phase inclusions are present in the Al-Cu-Yb alloy at the boundary between the eutectic and aluminum dendrites. The recrystallization starting temperature of the alloys is in the range of 250–350 °C after rolling with previous quenching at 590 and 605 °C for Al-Cu-Yb and Al-Cu-Gd, respectively. The hardness and tensile properties of Al-Cu-Yb and Al-Cu-Gd as-rolled alloys are reduced by increasing the annealing temperature and time. The as-rolled alloys have high mechanical properties: YS = 303 MPa, UTS = 327 MPa and El. = 3.2% for Al-Cu-Yb alloy, while YS = 290 MPa, UTS = 315 MPa and El. = 2.1% for Al-Cu-Gd alloy.

Microstructural Change of Beta Type Titanium Alloy by Intense Plastic Deformation

2006 ◽  
Vol 503-504 ◽  
pp. 705-710 ◽  
Author(s):  
Goroh Itoh ◽  
Hisashi Hasegawa ◽  
Tsing Zhou ◽  
Yoshinobu Motohashi ◽  
Mitsuo Niinomi
Keyword(s):  
Plastic Deformation ◽  
Work Hardening ◽  
Static Recrystallization ◽  
True Strain ◽  
Microstructural Change ◽  
Intense Plastic Deformation ◽  
Rolled Plate ◽  
Al Alloy ◽  
Hot Rolled ◽  
Zr Alloy

Usual static recrystallization treatment and a method to provide intense plastic deformation, ARB namely Accumulative Roll-Bonding, have been applied to two beta type titanium alloys, i.e. Ti-29Nb-13Ta-4.6Zr and Ti-15V-3Cr-3Sn-3Al. Microstructural change as well as work-hardening behavior was examined as a function of plastic strain. Both the work-hardening rate and the hardness at the initial as-hot-rolled state were smaller in the Ti-Nb-Ta-Zr alloy than in the Ti-V-Cr-Sn-Al alloy. Recrystallized grains of 14μm in size were obtained by the usual static recrystallization treatment, which was significantly smaller than that of the starting as-hot-rolled plate of 38μm. No significant change other than flattening and elongating of the original grains was found in the optical microscopic scale. It was revealed, however, from a TEM observation combined with selected area diffraction technique that geometric dynamic recrystallization occurred in the Ti-Nb-Ta-Zr alloy deformed at room temperature by a true strain of 5, resulting in an ultra-fine-grained microstructure where the grain size was roughly estimated to be about 100nm.

Characterization of Mg-Al Sheet Clad Materials Fabricated by Hot Rolling

2007 ◽  
Vol 26-28 ◽  
pp. 409-412 ◽  
Author(s):  
Jae Seol Lee ◽  
Hyeon Taek Son ◽  
Ki Yong Lee ◽  
Soon Sub Park ◽  
Dae Guen Kim ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Vickers Hardness ◽  
Hot Rolling ◽  
High Strength ◽  
Interface Layer ◽  
Rolling Temperature ◽  
Al Alloy ◽  
Clad Sheet ◽  
The Difference ◽  
Interface Layers

AZ31 Mg / 5083 Al clad sheet was fabricated by the hot rolling method and its mechanical properties were investigated in this study. The tensile strength and yield strength of Mg- Al clad samples were slightly higher than that of AZ31 Mg sample, resulting in high strength 5083 Al alloy. Also, in the case of the AZ31 Mg sample, tensile strength indicated different values to the rolling directions. The thickness of interface layers between magnesium and aluminum materials increased with increasing rolling temperature. The thickness of interface layer was about 1.2 μm and 1.6 μm, respectively. The difference of thickness on the interface layer with variation of rolling temperature was attributed to promote the diffusion between magnesium and aluminum materials. The Vickers hardness of Mg-Al interface layer was around 125 Hv. The interface layer composed of hard inter-metallic phases which may act a increment of Vickers hardness depending upon its thickness.

Improvement of Mechanical Properties and Corrosion Resistance by Deformation Induced Precipitation in Al-Zn-Mg-Cu Alloy

2017 ◽  
Vol 898 ◽  
pp. 179-190 ◽  
Author(s):  
Jin Rong Zuo ◽  
Long Gang Hou ◽  
Jin Tao Shi ◽  
Hua Cui ◽  
Lin Zhong Zhuang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Thermomechanical Treatment ◽  
High Strength ◽  
Alloy Sheet ◽  
Rolling Temperature ◽  
Al Alloy ◽  
Deformation Degree ◽  
Dynamic Aging ◽  
Final Rolling Temperature ◽  
Final Rolling

A final thermomechanical treatment (FTMT) including peak aging and subsequent dynamic aging was proposed to prepare 7055 Al alloy sheets. The optimization was based on nine well-planned orthogonal experiments. Three main processing conditions in the thermomechanical treatment for obtaining the optimum synthetic properties of 7055 (i.e. preheating temperature, final rolling temperature and deformation degree) were investigated. It was shown that the final rolling temperature is the most important factor among the three parameters, and the optimum properties (yield strength: 651 MPa, ultimate tensile strength: 660 MPa) of 7055 Al alloy sheet can be gained with preheating at 140oC and 40% deformation at 170oC. With dynamic aging, grain boundary precipitates became discontinuous without much coarsening of matrix precipitates, while they were continuously distributed after T6 aging. The present optimal FTMT process can improve the intergranular / exfoliation corrosion resistance without sacrificing the strength compared to T6 tempering. The present FTMT process as a good alternative can produce high-strength Al alloy sheets with high strength and good corrosion resistance efficiently and economically.

Structural Characterization and Corrosion Properties of BTESPT Silane Films on Surface of 2024-T6 Aluminium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1111-1116 ◽  
Author(s):  
Ming An Chen ◽  
Xuan Xie ◽  
Guo Fu Xu ◽  
Hui Zhong Li ◽  
Xin Ming Zhang
Keyword(s):  
Structural Characterization ◽  
Water Solution ◽  
Corrosion Current ◽  
Immersion Test ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Entire Surface ◽  
Corrosion Properties ◽  
The Matrix

2024-T6 Al alloy sheet s were modified by bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) silane film to improve the corrosion resistance. Fourier-Transform Reflection Absorption (FTIR-RA) spectroscopy was used for structural characterization of BTESPT silane film formed on surface of the sheet. Potentiodynamic polarization and immersion test in 3.5% NaCl solution were used for evaluating the corrosion performances of the silane film. The results showed that the film formed after curing at 120 °C for 40 min was cross-linked through Si-O-Si and that it was covered on the entire surface of the sheet. The content of elements S and Si on the Al2CuMg particles is a little higher that of on the matrix. The strong peak at 1032 cm-1 indicated that the film was linked to the sheet by Si-O-Al. Compared to the untreated case, the corrosion current density of the sheet treated with the silane film was reduced by close to 2 orders. Treatment of BTESPT silane can provide about 670 h protection of corrosion for the sheet in 3.5% NaCl water solution.

Numerical Experiments of Coolant Mixing in a Lower Plenum of PWR Under Asymmetric Thermal- Hydraulics Conditions

2006 ◽  
Author(s):  
Masanori Ohtani ◽  
Akito Kozuru ◽  
Yasuyuki Kashimoto ◽  
Mitsuto Montani ◽  
Koutaro Takeda ◽  
...  
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Turbulent Mixing ◽  
Numerical Experiments ◽  
Time Dependent ◽  
Inlet Temperature ◽  
Velocity Fluctuations ◽  
The Core ◽  
State Calculation ◽  
Lower Temperature

Asymmetric thermal-hydraulic conditions among primary loops during a postulated steam line break (SLB) induce a non-uniform temperature distribution at a core inlet. When coolant of lower temperature intrudes into a part of core, it leads to a reactivity insertion and a local power increase. Therefore, an appropriate model for the core inlet temperature distribution is required for a realistic SLB analysis. In this study, numerical experiments were conducted to examine the core inlet temperature distribution under the asymmetric thermal-hydraulic coolant conditions among primary loops. 3D steady-state calculations were carried out for Japanese standard Pressurized Water Reactor (PWR) such as 2, 3, 4 loop types and an advanced PWR. Since the flow in a reactor vessel involves time-dependent velocity fluctuations due to a high Reynolds number condition and a complicated geometry of flow path, the turbulent mixing might be enhanced. Hence, the turbulent thermal diffusivity for the steady-state calculation was examined based on experimental results and another transient calculation. As a result, it was confirmed that (1) the turbulent mixing in a downcomer and a lower plenum were enhanced due to time-dependent velocity fluctuations and therefore the turbulent thermal diffusivity for steady-state calculation was specified to be greater, (2) the core inlet temperature distribution predicted by a steady-state calculation reasonably agreed with a experimental data, (3) the patterns of core inlet temperature distribution were comprehended to be dependent on the plant type, i.e. the number of primary loop and (4) under a low flow rate condition, the coolant of lower temperature appeared on the opposite side of the affected loop due to the effect of a natural convection.

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