Investigation on the Strain Behaviour of a Precipitation-Hardenable Aluminium Alloy through a Temperature Gradient Based Heat Treatment

2015 ◽  
Vol 639 ◽  
pp. 361-368 ◽  
Author(s):  
Gabriella di Michele ◽  
Pasquale Guglielmi ◽  
Gianfranco Palumbo ◽  
Donato Sorgente
Keyword(s):  
Heat Treatment ◽  
Temperature Gradient ◽  
Aluminium Alloy ◽  
Room Temperature ◽  
Tensile Tests ◽  
Gauge Length ◽  
Image Correlation ◽  
Experimental Campaign ◽  
Strain Behaviour ◽  
Heat Treated

In this work the strain behaviour of the heat-treated 6xxx series aluminium alloy AC170PX is investigated by a not conventional approach. Thanks to the low density combined with good mechanical properties, this aluminium alloy is often adopted for automotive applications. Despite these advantages, its formability at room temperature is low. In order to overcome this limit, a distribution of the material properties can be achieved by a local heat treatment (Tailored Heat Treated Blanks). In this context, to evaluate the effects of those parameters mainly affecting the precipitation hardening (aging temperature and aging time), a first experimental campaign was conducted using conventional furnace heat treatment in different conditions . Tensile tests were run with the aim of determining the flow and the aging curves of the heat treated specimens. Starting from these results, a not uniform heat treatment was designed using a Gleeble physical simulator Heat treatments based on a temperature gradient along the sample were performed. Then, tensile tests of the so heated specimens were carried out at room temperature. Through a digital image correlation system both the distribution and the evolution of the strain along the gauge length of the specimen were analysed in order to obtain the hardening/softening working conditions related to a specific heating cycle. These results were validated by the comparison with the data obtained from the first experimental campaign.

Simulation of Heat Assisted Forming of Commercial Aluminium Alloy AA5182

2011 ◽  
Vol 473 ◽  
pp. 675-682 ◽  
Author(s):  
Rajarajan Govindarajan ◽  
Martin Zubeil ◽  
Kathleen Siefert ◽  
Christophe Ageorges ◽  
Karl Roll
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloy ◽  
Room Temperature ◽  
Heat Treating ◽  
Tensile Tests ◽  
Experimental Investigations ◽  
Body Parts ◽  
Cold Forming ◽  
Commercial Aluminium ◽  
Automotive Interior

To improve the formability of commercial aluminium alloy AA5182, a new heat assisted forming method is used. The process sequence of this method is; cold forming (pre-forming, 90 to 95% of final shape), heat treatment and cooling it down to room temperature and final cold forming. AA5182 is a non-heat treatable alloy and hence heat treating a strain hardened non-heat treatable aluminium alloy leads to lose in strength and gain in plastic recovery. Therefore by heat treating a preformed part and then following it up by further forming stages, it not only gains the lost strength back but also shows increased formability. This behavior is particularly useful in forming more complex automotive interior body parts. To accurately simulate this method, modeling the effect of heat treatment is important. Initial investigations on tensile tests showed that the degree of pre-forming in combination with heat treatment is directly proportional to plastic recovery. Which means, the more the pre-strain is the more the recovery becomes viable. Based on this, a new algorithm has been developed and implemented in LS-DYNA to capture the effect of heat treatment. Finally experimental investigations were carried out on a cross die deep drawn cup to validate the developed simulation model.

scholarly journals Measurement and Analysis of Heterogeneous Strain Fields in Uniaxial Tensile Tests for Boron Steel Under Hot Stamping Conditions

2020 ◽  
Vol 60 (9) ◽  
pp. 1289-1300
Author(s):  
R. Zhang ◽  
Z. Shao ◽  
J. Lin ◽  
T. A. Dean
Keyword(s):  
Temperature Gradient ◽  
Hot Stamping ◽  
Tensile Tests ◽  
Gauge Length ◽  
Image Correlation ◽  
Effect Of Temperature ◽  
Uniaxial Tensile ◽  
Boron Steel ◽  
Strain Fields ◽  
Dog Bone

Abstract Background A significant amount of uniaxial tensile tests has been carried out using Gleeble systems to investigate the viscoplastic deformation of boron steel (22MnB5) under hot stamping conditions. However, due to heat loss through the end clamps, a temperature gradient in the reduced parallel section of dog-bone shaped specimens is inevitable. Objective In the work reported in this paper, the effect of temperature gradient on measured outcomes is examined. Methods Uniaxial tensile tests on 1.5 mm thick boron steel specimens are carried out, under hot stamping conditions and strain fields are quantified using the digital image correlation (DIC) technique. The effect of gauge length on the properties of boron steel, as calculated from observed test results, is determined. Results Compared with the test at room temperature, a bell-shaped strain distribution occurs within the gauge length even before the appearance of the maximum load. Also, average strain within the gauge length, especially in the later stages, changes with gauge length within the investigated range, and thus, different engineering stress-strain curves and fracture strains are determined. In addition, normalized strain rate is significantly dependent on gauge length, which results in over 16% difference among the computed flow stresses by using a unified constitutive model. Conclusions The characterized properties of the material are dependent on gauge length and thus, a testing standard for measuring thermal-mechanical data of materials by using a Gleeble need to be defined.

A research on the effect of retrogression and re-aging heat treatment on hot tensile properties of AA7075 aluminum alloys

2021 ◽  
pp. 1-23
Author(s):  
Talha Sunar ◽  
Dursun Ozyurek
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Ductile Fracture ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Xrd Analysis ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Tensile Behaviour ◽  
Heat Treated

Abstract Aluminium alloys are preferred in most industries due to the functional properties they provide. It is known that alloys that can be processed with heat treatments shows better mechanical properties. 7xxx series alloys can be processed vi heat treatments and are often used in environmental conditions such as extreme temperatures and corrosive environments. Corrosive sensitivities such as stress corrosion cracking (SCC) can be observed with the effect of working conditions. It is known that retrogression and re-aging (RRA) heat treatment provide corrosion resistance and decrease the SCC velocity. The purpose of this study is to examine the tensile behaviour of annealed and retrogression-re-aging (RRA) heat treated AA7075 alloys at elevated temperatures. The mechanical properties of the alloys were investigated by conducting tensile tests at room temperature (RT), 100, 200, and 300°C. Hardness tests were performed at room temperature on the samples which were taken from tensile test specimens after tensile tests. The potential effects of test temperature on mechanical and microstructural properties were examined. The annealed and RRA heat treated alloys were characterized by scanning electron microscope (SEM), and X-ray diffraction (XRD) analysis. As a result, an increase in strength and hardness of the RRA treated AA7075 alloys was observed. Ductility of the RRA alloy was lower compared to the annealed AA7075 alloy. Fracture surface examinations showed that there was a semi-ductile fracture below 200°C and ductile fracture at temperatures of 200 and 300°C. Ductility was observed to increase with increasing temperature.

Influence of Heat Treatment on Microstructure and Mechanical Properties of Selective Laser Melted TiAl6V4 Alloy

2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Room Temperature ◽  
Base Alloy ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Treatment Procedures

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.

Inhomogeneous Strain Distribution in SiCf/SiC Coupons Under Tensile Loading

2017 ◽  
Author(s):  
Christopher D. Newton ◽  
Jonathan P. Jones ◽  
Adam L. Chamberlain ◽  
Martin R. Bache
Keyword(s):  
Mechanical Testing ◽  
Room Temperature ◽  
Ceramic Matrix Composites ◽  
Tensile Tests ◽  
Image Correlation ◽  
Failure Data ◽  
Inhomogeneous Strain ◽  
Ultimate Failure ◽  
Complex Structural ◽  
Structural Architecture

The complex structural architecture and inherent processing artefacts within ceramic matrix composites combine to induce inhomogeneous deformation and damage prior to ultimate failure. Bulk measurements of strain via extensometry or even localised strain gauging will fail to characterise such inhomogeneity when performing conventional mechanical testing on laboratory scaled coupons. The current research project has, therefore, applied digital image correlation (DIC) techniques to the room temperature axial assessment of a SiCf/SiC composite under static and ratchetted loading. As processed SiCf/SiC panels were subjected to detailed X-ray computed tomography (XCT) inspection prior to specimen extraction and subsequent mechanical testing. In situ DIC strain measurements were taken throughout the period of room temperature monotonic and ratchet style tensile tests. Contemporary acoustic emission (AE) signals were also recorded to indicate significant damage events and the onset of ultimate failure. Data from these separate monitoring techniques were correlated to indicate the sensitivity or otherwise to pre-existing artefacts within the as received CMC panels.

scholarly journals Influence of strain rate and heat treatments on tensile and creep properties of Zn-0.15Cu-0.07Ti alloys

DYNA ◽  
2016 ◽  
Vol 83 (195) ◽  
pp. 77-83 ◽  
Author(s):  
María José Quintana Hernández ◽  
José Ovidio García ◽  
Roberto González Ojeda ◽  
José Ignacio Verdeja
Keyword(s):  
Strain Rate ◽  
Room Temperature ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Strain Rates ◽  
Creep Tests ◽  
Design Problems ◽  
Creep Properties ◽  
Heat Treated ◽  
Zn Alloys

The use of Cu and Ti in Zn alloys improves mechanical properties as solid solution and dispersoid particles (grain refiners) may harden the material and reduce creep deformation. This is one of the main design problems for parts made with Zn alloys, even at room temperature. In this work the mechanical behavior of a Zn-Cu-Ti low alloy is presented using tensile tests at different strain rates, as well as creep tests at different loads to obtain the value of the strain rate coefficient m in samples parallel and perpendicular to the rolling direction of the Zn strip. The microstructure of the alloy in its raw state, as well as heat treated at 250°C, is also analyzed, as the banded structure produced by rolling influences the strengthening mechanisms that can be achieved through the treatment parameters.

scholarly journals Study on Fatigue Life of Heat-treated Aluminium alloy coated with Castor oil.

2018 ◽  
Vol 172 ◽  
pp. 03004
Author(s):  
A. Sivasubramanian ◽  
T.S. Kirubasankar ◽  
S. Vinoth kumar
Keyword(s):  
Heat Treatment ◽  
Fatigue Life ◽  
Aluminium Alloy ◽  
Castor Oil ◽  
Cyclic Load ◽  
Heat Treated ◽  
Al 7075 ◽  
Number Of Cycles ◽  
Uncoated Specimen ◽  
Scanning Electron

This paper involves the study of fatigue life of coated aluminium alloy Al 7075-T651 that is heat-treated under 100oC soaked in castor oil for three days. The specimen after heat treatment is subjected to fatigue test using rotary bending machine for number of cycles to fail under cyclic load of 15kgf, 25Kgf, and 50kgf.The life of the specimen is found and compared with uncoated specimen and improved life in number of cycle is noticed. The crack propagation and its type is analysed using scanning electron microscope for knowing the point of fracture and its initiation to failure.

scholarly journals Comparison of Different Heat Treatment Processes of Selective Laser Melted 316L Steel Based on Analysis of Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3805 ◽  
Author(s):  
Janusz Kluczyński ◽  
Lucjan Śnieżek ◽  
Krzysztof Grzelak ◽  
Artur Oziębło ◽  
Krzysztof Perkowski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Fracture Analysis ◽  
Image Correlation ◽  
Treatment Processes ◽  
Different Types ◽  
316L Steel ◽  
Precipitation Heat

In this study, we analyzed the mechanical properties of selectively laser melted (SLM) steel obtained via different modifications during and after the manufacturing process. The aim was to determine the effects of precipitation heat treatment on the mechanical properties of elements additively manufactured using three different process parameters. Some samples were additionally obtained using hot isostatic pressing (HIP), while some were treated using two different types of heat treatment and a combination of those two processes. From each manufactured sample, a part of the material was taken for structural analysis including residual stress analysis and microstructural investigations. In the second part of the research, the mechanical properties were studied to define the scleronomic hardness of the samples. Finally, tensile tests were conducted using a digital image correlation (DIC) test and fracture analysis. The treated samples were found to be significantly elongated, thus indicating the advantages of using precipitation heat treatment. Additionally, precipitation heat treatment was found to increase the porosity of samples, which was the opposite compared to HIP-treated samples.

The Effect of Heat Treatment on Fatigue and Mechanical Properties of 6061 Aluminium Alloy

2014 ◽  
Vol 699 ◽  
pp. 227-232
Author(s):  
Nurulhilmi Zaiedah Nasir ◽  
Mohd Ahadlin Mohd Daud ◽  
Mohd Zulkefli Selamat ◽  
Ahmad Rivai ◽  
Sivakumar Dhar Malingam
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Strength ◽  
Aluminium Alloy ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Hardness Tester ◽  
Quenching Media ◽  
Heat Treated ◽  
6061 Aluminium Alloy

This paper investigated the effect of heat treatment on mechanical properties and microstructure of 6061 aluminium alloy. The aluminium alloys were examined in the heat treated conditions, using different quenching media, water and oil. The alloy was solution heat treated at temperature of 529oC for one, three and five hour respectively. Aging treatment was carried out at temperature of 160oC which is assumed to be the best temperature for ageing process. Hardness measurement was carried out using a Brinell Hardness Tester Machine. The results shows hardness and impact strength are inversely proportional to each other, as the hardness of 6061 aluminium alloy decreases and impact strength increases.

Analysis of Strain Hardening Behaviour of Cast Aluminium Alloy 354 Subjected to Artificial Ageing at Various Temperatures

2013 ◽  
Vol 856 ◽  
pp. 231-235 ◽  
Author(s):  
Aditya Eswar ◽  
Arnav Gupta ◽  
G. Dinesh Babu ◽  
M. Nageswara Rao
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloy ◽  
Strain Hardening ◽  
Automotive Industry ◽  
Mechanical Behaviour ◽  
Artificial Ageing ◽  
Cast Aluminium ◽  
Heat Treated ◽  
Lower Strain ◽  
Wide Scale

Automotive industry makes wide scale use of cast aluminium alloy 354 in the production of crucial components, such as compressor wheels for turbochargers. The compressor wheels undergo T61 heat treatment, involving artificial ageing at 188°C. This study focuses on the possible improvement of the mechanical behaviour of the components by subjecting them to modified heat treatments involving usage of lower artificial ageing temperatures (160, 171 and 177°C). A comparative analysis of tensile properties and strain hardening behaviour has been carried out with different artificial ageing temperatures. Results showed that the heat treatment routinely employed by the industry (aged at 188°C) leads to overageing, thereby resulting in relatively inferior mechanical properties and lower strain hardening rates as compared to the samples heat treated at lower artificial ageing temperatures. It is concluded that lowering of the artificial ageing temperature can lead to a superior state of components with respect to mechanical behaviour.

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