INFLUENCE OF TEMPERATURE AND STRAIN RATE ON SUPERPLASTICITY KINETICS OF COMPOSITE AZ61-F MAGNESIUM MATERIALS

Micromechanisms of fracture of AZ61-F composites in the zone of quasi-superplastic deformation were analyzed and quantified in this work. Deformation of AZ61-F magnesium alloys with 1 wt.% of Al2O3 phase was tested at a temperature of 473 K and different strain rates. It was shown that at the temperature of 473 K and the highest strain rate applied from 1× 10−2 to 1 × 10−4 s−1, a significant growth of ductility was observed. The mean dimples diameter of the ductile fracture decreased with the decreasing strain rate. The grain size of 0.7 μm was reached by severe plastic deformation using equal channel angular pressing (ECAP). Secondary Mg17Al12 and Al2O3 phases were identified. The maximum strain was reached at the temperature of 473 K and strain rate of 1 × 10−4 s−1.

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Superplasticity in a 5024 Aluminium Alloy Processed by Severe Plastic Deformation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.735.353 ◽

2012 ◽

Vol 735 ◽

pp. 353-358 ◽

Cited By ~ 5

Author(s):

Anna Mogucheva ◽

Diana Tagirova ◽

Rustam Kaibyshev

Keyword(s):

Plastic Deformation ◽

Severe Plastic Deformation ◽

Strain Rate ◽

Aluminium Alloy ◽

Initial Strain Rate ◽

Strain Rates ◽

Superplastic Behaviour ◽

Angular Pressing ◽

Elongation To Failure ◽

Zr Alloy

The superplastic behaviour of an Al-4.6%Mg-0.35%Mn-0.2%Sc-0.09%Zr alloy was studied in the temperature range 250-500°C at strain rates ranging from 10-4 to 10-1 s-1. The AA5024 was subjected to equal channel angular pressing (ECAP) at 300°C up to ~12. The highest elongation-to-failure of ∼3300% was attained at a temperature of 450°C and an initial strain rate of 5.6×10-1 s-1. Regularities of superplastic behaviour of the 5024 aluminium alloy are discussed.

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Micromechanisms of Fracture of Magnesium Based Composite After Superplastic Deformation

Powder Metallurgy Progress ◽

10.1515/pmp-2016-0010 ◽

2016 ◽

Vol 16 (2) ◽

pp. 117-122 ◽

Cited By ~ 1

Author(s):

Beáta Ballóková ◽

Katarína Sülleiová ◽

Michal Besterci ◽

Oksana Velgosová ◽

Song-Jeng Huang

Keyword(s):

Statistical Analysis ◽

Elevated Temperature ◽

Strain Rate ◽

Superplastic Deformation ◽

Strain Rates ◽

Significant Growth ◽

Micromechanisms Of Fracture ◽

Maximum Value

Abstract The micromechanisms of fracture of AZ61 + 1 wt. % Al2O3 composite in the zone of superplastic deformation was analysed and quantified in this work. The specimens were tested at temperature of 200°C at different strain rates. Changing the strain rate, from 1x10-2 s-1 to 1x10-4 s-1, a significant growth of ductility was observed. At maximum value of superplasticity the fracture was transcrystalline ductile with dimples of two size categories. Based on the statistical analysis of fracture micromechanisms at the elevated temperature and strain rates of 10-0- 1x10-4 s-1 hyperbolic dependency was depicted according to Gurland - Plateau theory.

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Contribution to Kinetics of Superplastic Deformation of Dispersion Strengthened Al-Al4C3 System

High Temperature Materials and Processes ◽

10.1515/htmp.2011.121 ◽

2012 ◽

Vol 31 (1) ◽

Author(s):

Michal Besterci ◽

Marián Varchola ◽

Ladislav Kováč ◽

Oksana Velgosová

Keyword(s):

Strain Rate ◽

Superplastic Deformation ◽

Constant Strain Rate ◽

Superplastic Behavior ◽

Influence Of Temperature ◽

Kinetics Of

AbstractThe influence of temperature at constant strain rate has been evaluated with respect to superplastic behavior of dispersion strengthened Al-Al

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Superplastic Behaviour of AZ61-F Magnesium Composite Materials

High Temperature Materials and Processes ◽

10.1515/htmp-2016-0026 ◽

2017 ◽

Vol 36 (3) ◽

pp. 279-283 ◽

Cited By ~ 1

Author(s):

Michal Besterci ◽

Katarína Sülleiová ◽

Oksana Velgosová ◽

Beáta Balloková ◽

S.-J. Huang

Keyword(s):

Grain Size ◽

Composite Materials ◽

Strain Rate ◽

Magnesium Alloys ◽

Equal Channel Angular Pressing ◽

Strain Rates ◽

Maximum Strain ◽

Plastic Deformations ◽

Angular Pressing ◽

Different Temperatures

AbstractDeformation of AZ61-F magnesium alloys with 1 wt % of Al2O3phase was tested at different temperatures and different strain rates. It was shown that at temperatures 473–523 K and the highest strain rate applied from 1×10–2s–1to 1×10–4s–1, a significant ductility growth was observed. The grain size of 0.6–0.8 μm was reached by severe plastic deformations by means of equal channel angular pressing (ECAP). Secondary Mg17Al12and Al2O3phases were identified. Maximum strain was gained at temperature of 473 K and strain rate of 1×10–4s–1.

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Local Investigations of the Mechanical Properties of Ultrafine Grained Metals by Nanoindentations

Materials Science Forum ◽

10.4028/www.scientific.net/msf.503-504.31 ◽

2006 ◽

Vol 503-504 ◽

pp. 31-36 ◽

Cited By ~ 17

Author(s):

Johannes Mueller ◽

Karsten Durst ◽

Dorothea Amberger ◽

Matthias Göken

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Room Temperature ◽

Rate Sensitivity ◽

Strain Rates ◽

Fcc Metals ◽

Angular Pressing ◽

Ultrafine Grained ◽

Indentation Strain

The mechanical properties of ultrafine-grained metals processed by equal channel angular pressing is investigated by nanoindentations in comparison with measurements on nanocrystalline nickel with a grain size between 20 and 400 nm produced by pulsed electrodeposition. Besides hardness and Young’s modulus measurements, the nanoindentation method allows also controlled experiments on the strain rate sensitivity, which are discussed in detail in this paper. Nanoindentation measurements can be performed at indentation strain rates between 10-3 s-1 and 0.1 s-1. Nanocrystalline and ultrafine-grained fcc metals as Al and Ni show a significant strain rate sensitivity at room temperature in comparison with conventional grain sized materials. In ultrafine-grained bcc Fe the strain rate sensitivity does not change significantly after severe plastic deformation. Inelastic effects are found during repeated unloading-loading experiments in nanoindentations.

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The Domain of Portevin-Le Chatelier Effect in Al-3Mg Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.928 ◽

2021 ◽

Vol 1016 ◽

pp. 928-933

Author(s):

Anna Mogucheva ◽

Diana Yuzbekova ◽

Yuliya Igorevna Borisova

Keyword(s):

Cold Rolling ◽

Strain Rate ◽

Uniform Elongation ◽

Deformation Curve ◽

Strain Rates ◽

Deformation Curves ◽

Angular Pressing ◽

Lower Strain ◽

Chatelier Effect ◽

General Deformation

An Al-3Mg (wt. %) alloy was studied after equal channel angular pressing and subsequent cold rolling. The mechanical behavior of the alloy in the temperature range from 223 K to 373 K (from –50°C to 125°C) at strain rates 2.1×10–1 – 5.2×10–5 s–1 was investigated. The analysis of stress-strain curves was performed to determine the conditions of manifestation of the Portevin – Le Chatelier (PLC) effect in investigated alloy. The deformation curve at a temperature of 298 K (25°C) and a strain rate of 1×10–3 s–1 is characterized by instability of plastic flow in contrast to the deformation curves obtained under other studied strain rate/temperature conditions. Stress oscillations at the necking stage were observed at high temperatures (>323 K (50°C)) and lower strain rates (1×10–4 s–1 and 5.2×10–5 s–1) forming the left border of the PLC effect domain. In general, deformation curves are characterized by the absence of stress serrations during the uniform elongation.

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Comparative Study of the Dynamic Behavior of AA2519 Aluminum Alloy in T6 and T8 Temper Conditions

Volume 9: Mechanics of Solids, Structures, and Fluids ◽

10.1115/imece2019-10978 ◽

2019 ◽

Author(s):

Adewale Olasumboye ◽

Gbadebo Owolabi ◽

Olufemi Koya ◽

Horace Whitworth ◽

Nadir Yilmaz

Keyword(s):

Plastic Deformation ◽

Aluminum Alloy ◽

Stress Response ◽

Flow Stress ◽

Yield Strength ◽

Strain Rate ◽

High Strain ◽

Second Phase ◽

Strain Rates ◽

High Strain Rates

Abstract This study investigates the dynamic response of AA2519 aluminum alloy in T6 temper condition during plastic deformation at high strain rates. The aim was to determine how the T6 temper condition affects the flow stress response, strength properties and microstructural morphologies of the alloy when impacted under compression at high strain rates. The specimens (with aspect ratio, L/D = 0.8) of the as-cast alloy used were received in the T8 temper condition and further heat-treated to the T6 temper condition based on the standard ASTM temper designation procedures. Split-Hopkinson pressure bar experiment was used to generate true stress-strain data for the alloy in the range of 1000–3500 /s strain rates while high-speed cameras were used to monitor the test compliance with strain-rate constancy measures. The microstructures of the as received and deformed specimens were assessed and compared for possible disparities in their initial microstructures and post-deformation changes, respectively, using optical microscopy. Results showed no clear evidence of strain-rate dependency in the dynamic yield strength behavior of T6-temper designated alloy while exhibiting a negative trend in its flow stress response. On the contrary, AA2519-T8 showed marginal but positive response in both yield strength and flow behavior for the range of strain rates tested. Post-deformation photomicrographs show clear disparities in the alloys’ initial microstructures in terms of the second-phase particle size differences, population density and, distribution; and in the morphological changes which occurred in the microstructures of the different materials during large plastic deformation. AA2519-T6 showed a higher susceptibility to adiabatic shear localization than AA2519-T8, with deformed and bifurcating transformed band occurring at 3000 /s followed by failure at 3500 /s.

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High Strain Rate Superplasticity in Al-Zn-Mg-Based Alloy: Microstructural Design, Deformation Behavior, and Modeling

Materials ◽

10.3390/ma13092098 ◽

2020 ◽

Vol 13 (9) ◽

pp. 2098 ◽

Cited By ~ 1

Author(s):

Olga Yakovtseva ◽

Maria Sitkina ◽

Ahmed O. Mosleh ◽

Anastasia Mikhaylovskaya

Keyword(s):

High Strain Rate ◽

Strain Rate ◽

Superplastic Deformation ◽

High Strain ◽

Flow Behavior ◽

Constant Strain Rate ◽

Superplastic Forming ◽

High Strength ◽

Strain Rate Range ◽

Strain Rates

Increasing the strain rate at superplastic forming is a challenging technical and economic task of aluminum forming manufacturing. New aluminum sheets exhibiting high strain rate superplasticity at strain rates above 0.01 s−1 are required. This study describes the microstructure and the superplasticity properties of a new high-strength Al-Zn-Mg-based alloy processed by a simple thermomechanical treatment including hot and cold rolling. The new alloy contains Ni to form Al3Ni coarse particles and minor additions of Zr (0.19 wt.%) and Sc (0.06 wt.%) to form nanoprecipitates of the L12-Al3 (Sc,Zr) phase. The design of chemical and phase compositions of the alloy provides superplasticity with an elongation of 600–800% in a strain rate range of 0.01 to 0.6/s and residual cavitation less than 2%. A mean elongation-to-failure of 400% is observed at an extremely high constant strain rate of 1 s−1. The strain-induced evolution of the grain and dislocation structures as well as the L12 precipitates at superplastic deformation is studied. The dynamic recrystallization at superplastic deformation is confirmed. The superplastic flow behavior of the proposed alloy is modeled via a mathematical Arrhenius-type constitutive model and an artificial neural network model. Both models exhibit good predictability at low and high strain rates of superplastic deformation.

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