Roll Bonding of Two Materials Using Temperature to Compensate the Material Strength Difference

2014 ◽  
Vol 966-967 ◽  
pp. 471-480 ◽  
Author(s):  
Alina Melzner ◽  
Gerhard Hirt
Keyword(s):  
Surface Layer ◽  
Atmospheric Corrosion ◽  
Pure Aluminum ◽  
High Strength ◽  
Cooling Time ◽  
Core Material ◽  
Material Strength ◽  
Roll Bonding ◽  
Strength Difference ◽  
High Strength Aluminum Alloys

A part with optimized material characteristics can be realized by cladding of two or more materials. In the aerospace industry high strength aluminum alloys like AA2024 are commonly used. Due to their susceptibility to atmospheric corrosion a protective surface layer has to be provided, e.g. pure aluminum. Because of high differences in material strength problems occur during bonding. This study discusses if and how active cooling can be used to create a temperature field which compensates the material strength difference and thus improves roll bonding of two materials of different strength. Cooling simulations were carried out to investigate the influence of the boundary conditions and cooling time before hot rolling for different layer thicknesses. For the example of a thick core (50 mm) and a thinner cover layer (10 mm) the optimal cooling time was determined to be in a range of 3 - 14 s. Furthermore, roll bonding experiments were performed at various height reductions and cooling times to investigate the influence of the material strength differences on the rolling and bonding behavior. Due to the implementation of a cooling operation a varying elongation of the surface layer and the core material has been successfully reduced from 30 to 22 mm.

Improved Atmospheric Corrosion Testing for Aluminum Alloys, Part II: Developing Improved Testing Protocol

CORROSION ◽  
10.5006/3335 ◽  
2019 ◽  
Vol 76 (1) ◽  
pp. 51-62
Author(s):  
Mary E. Parker ◽  
Robert G. Kelly
Keyword(s):  
Aluminum Alloys ◽  
Atmospheric Corrosion ◽  
Salt Spray ◽  
High Strength ◽  
Corrosion Testing ◽  
Short Exposure ◽  
Wetting And Drying ◽  
Short Exposure Time ◽  
High Strength Aluminum Alloys ◽  
Dwell Period

A modified version of ASTM G85-A2 was developed in this work with the intention of targeting a relative humidity (RH) of 75% during the dwell period. The outcome was two different RH profiles, one that averaged 74% RH during the dwell period and another that averaged 61.5% RH during the dwell period. Both tests produced moderate exfoliation in AA2060-T3 after just 12 days of exposure. Other high-strength aluminum alloys (AA7075, AA2024) were exposed to the modified RH profiles, and both tests could correctly differentiate exfoliation resistance for these alloys. An average RH between 74% and 61.5% during the dwell period was found to produce consistent exfoliation ratings after a short exposure time. Electrochemical measurements made during salt spray testing were used to propose electrochemical mechanisms that occur during wetting and drying in atmospheric corrosion testing.

Finite Element Implementation of a Bonding Model and Application to Roll Bonding of Aluminum Sheets of Largely Different Yield Strength

2014 ◽  
Vol 783-786 ◽  
pp. 644-650 ◽  
Author(s):  
Markus Bambach ◽  
Michael P. Pietryga ◽  
A. Mikloweit ◽  
Gerhard Hirt ◽  
Kai F. Karhausen
Keyword(s):  
Finite Element ◽  
Aluminum Alloys ◽  
Yield Strength ◽  
Bond Strength ◽  
Pure Aluminum ◽  
Core Material ◽  
Shear Stresses ◽  
Roll Bonding ◽  
Aluminum Sheets ◽  
Roll Gap

Roll bonding is a joining-by-forming operation, in which two or more metallic strips or plates are bonded permanently through the pressure and plastic deformation in the roll gap. Although roll bonding has been successfully used in industrial production over many years, difficulties occur especially when materials of largely different yield strength are roll-bonded, e.g. when hard aluminum alloys are clad with soft commercially pure aluminum. Examples are AA2024 sheets used in wing and fuselage structures of aircrafts, which are clad with AA1050 to improve the corrosion resistance. Likewise, aluminum sheets for heat exchangers consist of a hard base material that is clad with a soft solderable aluminum alloy. In these cases, the strength difference may influence the bonding behavior since the softer face sheet has to transmit the deformation to the harder core material. To analyze and optimize such cases, a bonding model integrated into a numerical framework for the simulation of the roll bonding process is required. In this paper, a finite element model is presented, in which the development of bond strength is simulated using a cohesive contact formulation. The model is used to study the bonding behavior of laboratory-scale roll bonding trials of two aluminum alloys with a large difference in yield strength. It is found that shear stresses are generated towards the end of the roll gap that may exceed the shear bond strength created earlier in the roll gap such that no firm bond is obtained. The conditions under which bonding is successful are analyzed using a finite element simulation study with varying yield stress differences and pass reductions and summarized in a map.

Precipitation strengthening of aluminum alloys by room-temperature cyclic plasticity

Science ◽  
2019 ◽  
Vol 363 (6430) ◽  
pp. 972-975 ◽  
Author(s):  
Wenwen Sun ◽  
Yuman Zhu ◽  
Ross Marceau ◽  
Lingyu Wang ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Room Temperature ◽  
High Strength ◽  
Cyclic Plasticity ◽  
Material Strength ◽  
Thermal Treatments ◽  
Dynamic Precipitation ◽  
Number Density ◽  
High Number Density ◽  
High Strength Aluminum Alloys

High-strength aluminum alloys are important for lightweighting vehicles and are extensively used in aircraft and, increasingly, in automobiles. The highest-strength aluminum alloys require a series of high-temperature “bakes” (120° to 200°C) to form a high number density of nanoparticles by solid-state precipitation. We found that a controlled, room-temperature cyclic deformation is sufficient to continuously inject vacancies into the material and to mediate the dynamic precipitation of a very fine (1- to 2-nanometer) distribution of solute clusters. This results in better material strength and elongation properties relative to traditional thermal treatments, despite a much shorter processing time. The microstructures formed are much more uniform than those characteristic of traditional thermal treatments and do not exhibit precipitate-free zones. These alloys are therefore likely to be more resistant to damage.

Deformation and fracture behavior of an Al-Li-Cu-Mg-Zr alloy 8090

1990 ◽  
Vol 48 (4) ◽  
pp. 974-975
Author(s):  
D.M. Jiang ◽  
B.D. Hong
Keyword(s):  
High Strength ◽  
Deformation And Fracture ◽  
Fracture Behaviors ◽  
Aluminum Lithium ◽  
Carbon Fiber Reinforced Composites ◽  
Peak Aged ◽  
Aluminum Lithium Alloys ◽  
High Strength Aluminum Alloys ◽  
Lithium Alloys ◽  
Zr Alloy

Aluminum-lithium alloys have been recently got strong interests especially in the aircraft industry. Compared to conventional high strength aluminum alloys of the 2000 or 7000 series it is anticipated that these alloys offer a 10% increase in the stiffness and a 10% decrease in density, thus making them rather competitive to new up-coming non-metallic materials like carbon fiber reinforced composites.The object of the present paper is to evaluate the inluence of various microstructural features on the monotonic and cyclic deformation and fracture behaviors of Al-Li based alloy. The material used was 8090 alloy. After solution treated and waster quenched, the alloy was underaged (190°Clh), peak-aged (190°C24h) and overaged (150°C4h+230°C16h). The alloy in different aging condition was tensile and fatigue tested, the resultant fractures were observed in SEM. The deformation behavior was studied in TEM.

AK STEEL NITRONIC 30

Alloy Digest ◽  
2013 ◽  
Vol 62 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Abrasion Resistance ◽  
Atmospheric Corrosion ◽  
High Strength ◽  
Good Resistance ◽  
Temperature Performance

Abstract AK Steel Nitronic 30 has good wet abrasion resistance, good resistance to aqueous and atmospheric corrosion, high strength, economy, and improved stress-corrosion cracking resistance over common 18-8 stainless steels. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming and joining. Filing Code: SS-1138. Producer or source: AK Steel Corporation.

DYNALLOY

Alloy Digest ◽  
1957 ◽  
Vol 6 (4) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Atmospheric Corrosion ◽  
High Strength ◽  
Heat Treating ◽  
Carbon Steels ◽  
Rolled Steel ◽  
Bend Strength ◽  
Steel Company

Abstract DYNALLOY is a versatile low-alloy, high-strength, flat rolled steel which combines high physical properties with ductility and weldability. It has higher atmospheric corrosion resistance, and also higher resistance to abrasion, impact and fatigue than plain carbon steels. This datasheet provides information on composition, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-56. Producer or source: Alan Wood Steel Company.

Formation of surface layer of hydrogen in pure aluminum

2019 ◽  
Vol 484 (1) ◽  
pp. 56-60
Author(s):  
D. A. Indejtsev ◽  
E. V. Osipova
Keyword(s):  
Surface Layer ◽  
Hydrogen Atom ◽  
Ab Initio ◽  
Pure Aluminum ◽  
Hydrogen Atoms ◽  
Energy Characteristics ◽  
Aluminum Crystal

Hydrogen atom behavior in pure aluminum is described by ab initio modelling. All main energy characteristics of the system consisting of hydrogen atoms in a periodic aluminum crystal are found.

Effect of diamond burnishing parameters on the state of the processed surface layer of billets made of high-strength "30ХГСН2А-ВД" steel

2020 ◽  
pp. 82-86
Author(s):  
A.N. Shvetsov ◽  
D.L. Skuratov
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Strain Hardening ◽  
Processing Speed ◽  
Synthetic Diamond ◽  
High Strength ◽  
The State ◽  
Diamond Burnishing

The influence of the burnishing force, tool radius, processing speed and feed on the distribution of circumferential and axial residual strses, microhardness and the depth of strain hardening in the surface layer when pr ssing of "30ХГСН2А-ВД" steel with synthetic diamond "ACB-1" is considered. Empirical dependencies determining these parameters are given. Keywords diamond burnishing, strain hardening depth, circumferential residual stresses, axial residual stresses, microhardness. [email protected], [email protected]

Mechanical Properties and Aging Behavior of Ultrafine Grained Al-Ag Alloy Fabricated by Accumulative Roll-Bonding

2014 ◽  
Vol 794-796 ◽  
pp. 851-856
Author(s):  
Tadashiege Nagae ◽  
Nobuhiro Tsuji ◽  
Daisuke Terada
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Accumulative Roll Bonding ◽  
Precipitation Hardening ◽  
Tensile Elongation ◽  
Solution Treatment ◽  
High Strength ◽  
Subsequent Aging ◽  
Roll Bonding ◽  
Ultrafine Grained

Accumulative roll-bonding (ARB) process is one of the severe plastic deformation processes for fabricating ultrafine grained materials that exhibit high strength. In aluminum alloys, aging heat treatment has been an important process for hardening materials. In order to achieve good mechanical properties through the combination of grain refinement hardening and precipitation hardening, an Al-4.2wt%Ag binary alloy was used in the present study. After a solution treatment at 550°C for 1.5hr, the alloy was severely deformed by the ARB process at room temperature (RT) up to 6 cycles (equivalent strain of 4.8). The specimens ARB-processed by various cycles (various strains) were subsequently aged at 100, 150, 200, 250°C, and RT. The hardness of the solution treated (ST) specimen increased by aging. On the other hand, hardness of the ARB processed specimen decreased after aging at high temperatures such as 250°C. This was probably due to coarsening of precipitates or/and matrix grains. The specimen aged at lower temperature showed higher hardness. The maximum harnesses achieved by aging for the ST specimen, the specimens ARB processed by 2 cycles, 4 cycles and 6 cycles were 55HV, 71HV, 69HV and 65HV, respectively. By tensile tests it was shown that the strength increased by the ARB process though the elongation decreased significantly. However, it was found that the tensile elongation of the ARB processed specimens was improved by aging without sacrificing the strength. The results suggest that the Al-Ag alloy having large elongation as well as high strength can be realized by the combination of the ARB process for grain refinement and the subsequent aging for precipitation hardening.

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