Effects of Pre-Ageing on Thermomechanical Treatment Process of 2A12 Aluminum Alloy

2012 ◽  
Vol 217-219 ◽  
pp. 283-287
Author(s):  
Shi Xing Zhang ◽  
Yu Ping Zhu ◽  
Hai Hong Wu
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Thermomechanical Treatment ◽  
Treatment Process ◽  
Great Increase ◽  
Second Phase ◽  
Small Particles ◽  
Aging Parameter

The thermomechanical treatment of a 2A12 aluminum alloy was researched and the influence of pre-ageing on microstructure and hardness was analyzed emphatically. The results reveal that the hardness of specimen increases when they are pre-aged, the hardness value rises at first and then decreases, reaching the maxmum value when pre-aged at 180°C×30min . After plastically deformed at 450°C, the hardness keeps on increasing, and the grains are equiaxed polygon structure. After all the workpieces are aged in the end, the small particles of the second phase precipitates completely and disperses within the original phase matrix, the particles interact with dislocations in upper state that formed during plastic deformation and lead to a great increase in hardness compared with as-received. the best pre-aging parameter is 180°C×30min.

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

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.

Effects of Thermomechanical Treatment Process on the Microstructure and Properties of 7A04 Aluminum Alloy

2011 ◽  
Vol 335-336 ◽  
pp. 805-808 ◽  
Author(s):  
Shi Xing Zhang ◽  
Hai Hong Wu ◽  
Gang Yi Cai
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Thermomechanical Treatment ◽  
Ageing Time ◽  
Solution Treatment ◽  
Second Phase ◽  
Microstructure And Properties ◽  
Treatment Processes ◽  
Phase Precipitate ◽  
Peak Value

The mechanical properties of a 7A04 aluminum alloy were improved by deformation strengthening and phase transformations strengthening adopting thermomechanical treatment, whose process include solution treatment, deformation treatment and ageing treatment in turn. The paper focuses on the influences of deforming degree and ageing process on microstructure and properties of 7A04 aluminum alloy. The experimental results show that hardness increased with increasing deformation ratio, and the value are greatly higher than that of samples after solution treatment. The results of ageing after deformation show that the hardness enhanced with prolonging the ageing time, which reach the peak value at 16 hours. In addition, the microstructure became more homogeneous and the grain was refined obviously by metallography microscope observation. The second phase precipitate dispersedly to strengthen the alloy. Above all, in order to obtain the better mechanical properties, the optimal thermomechanical treatment processes are solution treatment at 470°C for 2h, deformation with ratio of 40% as well as ageing at 120°C for 16h.

Effects of Thermomechanical Treatment Process on the Microstructure and Properties of Al-Zn-Mg Alloy

2011 ◽  
Vol 239-242 ◽  
pp. 847-850
Author(s):  
Gang Yi Cai ◽  
Yu Yong Yang ◽  
Xiao Hua Li
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Thermomechanical Treatment ◽  
Ageing Time ◽  
Solution Treatment ◽  
Second Phase ◽  
Microstructure And Properties ◽  
Treatment Processes ◽  
Phase Precipitate ◽  
Peak Value

The mechanical properties of Al-Zn-Mg aluminum alloy were improved by deformation strengthening and transformations strengthening adopting thermomechanical treatment, whose process are solution treatment, preageing treatment, deformation treatment and ageing treatment in turn. The paper focuses on the influences of deforming degree and ageing process on microstructure and properties of Al-Zn-Mg aluminum alloy. The experimental results show that hardness increased with increasing deformation ratio, and the value are greatly higher than that of samples after solution treatment. The results of ageing after deformation show that the hardness enhanced with prolonging the ageing time, which reach the peak value at 16 hours. In addition, the microstructure became more homogeneous and the grain was refined obviously by metallography microscope observation. The second phase precipitate dispersedly to strengthen the alloy. Above all, in order to obtain the better mechanical properties, the optimal thermomechanical treatment processes are solution treatment at 470°C for 2h, preageing treatment at 140°C for 24h, deformation with ratio of 40% as well as ageing at 120°C for 16h.

Effects of Solution and Two-Stage Ageing Treatment Process on Microstructure and Properties of 6061 Aluminum Alloy

2011 ◽  
Vol 335-336 ◽  
pp. 822-825
Author(s):  
Shi Xing Zhang ◽  
Gang Yi Cai ◽  
Hai Hong Wu
Keyword(s):  
Aluminum Alloy ◽  
Treatment Process ◽  
Solution Treatment ◽  
Processing Parameters ◽  
Second Phase ◽  
Dispersion Strengthening ◽  
Two Stage ◽  
6061 Aluminum Alloy ◽  
Ageing Treatment ◽  
Peak Value

Comprehensive performance of 6061 aluminum alloy was improved by solution treatment and two-step ageing treatment in this paper . The effects of different thermal processing parameters on the microstructure and mechanical properties of 6061 aluminum alloy were studied. The experimental results show that the optimal process of solution treatment for 6061 aluminum alloy is heated at 500°C for 10min. After first-stage aging, the hardness measurements and microstructure analysis results show that the hardness increased with increasing aging temperature, and reached peak value at temperature 180°C for 10h, while in the second-stage ageing treatment, the sample got the ageing peak value at 220°C for 1h. After two-stage treatment, the grains of 6061 aluminum alloy became uniform and fine and the second phase distributed along the grain boundary and play an important role of dispersion strengthening. Above all, the optimal heat treatment process of 6061 aluminum alloy is solution treated at 500°C for 10min, as well as ageing at 180°C, 10h and 220°C, 1h

Effects of Deformation Ratio above Recrystallizaton Temperature on Microstructure and Properties of 2A12 Aluminum Alloy

2012 ◽  
Vol 217-219 ◽  
pp. 279-282
Author(s):  
Shi Xing Zhang ◽  
Yu Ping Zhu ◽  
Gang Yi Cai
Keyword(s):  
Aluminum Alloy ◽  
Thermomechanical Treatment ◽  
Microscope Observation ◽  
Recrystallization Temperature ◽  
Second Phase ◽  
Microstructure And Properties ◽  
Deformation Ratio

The thermomechanical treatment of a 2A12 aluminum alloy was researched and the influence of deformation ratio above recrystallization temperature on microstructure and hardness was analyzed emphatically. The result reveals that when the deformation ratio is low at first, the hardness of specimen decreased because the effect of recrystallization softening overwhelms the effect of deformation strengthening. However, hardness increased with increasing deformation ratio. In addition, the microstructure became more homogeneous and grains were refined obviously by metallography microscope observation with increasing deformation ratio. The second phase precipitates dispersedly to strengthen the alloy.

scholarly journals Mathematical Modeling of Plastic Deformation of a Tube from Dispersion-Hardened Aluminum Alloy in an Inhomogeneous Temperature Field

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1103
Author(s):  
Oleg Matvienko ◽  
Olga Daneyko ◽  
Tatiana Kovalevskaya
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Temperature Difference ◽  
Wall Temperature ◽  
Volume Fraction ◽  
Tube Wall ◽  
Absolute Temperature ◽  
Second Phase ◽  
Tube Wall Temperature ◽  
Higher Temperature

The effect of temperature distribution on a stress–strain state tube made of disperse-hardened aluminum alloy subjected to internal pressure was investigated. The mathematical model is based on equations of physical plasticity theory and principles of mechanics of deformable solids. The results of this investigation demonstrate that varying the outer wall temperature in the range of 200 K at a fixed temperature of the inner wall leads to a significant change in the plastic resistance limit (for the considered tube sizes, this change is approximately 15%). An increase of the tube wall temperature reduces the resistance to plastic deformation. For the same absolute temperature difference between the outer and inner walls, the plastic resistance limit is less for the higher temperature of the inner wall of the tube. A decrease of the distances between the hardening particles at the same volume fraction of second phase leads to a significant increase in the pressure required to achieve plastic deformation of the tube walls. An increase in tube wall temperature reduces the resistance to plastic deformation. For the same absolute temperature difference between the outer and inner walls, the plastic resistance limit is lower for the higher temperature of the inner tube wall. The decrease of the distance between the hardening particles at the same volume fraction of the second phase leads to a significant increase in the pressure required to achieve plastic deformation of the tube walls.

Stereo Electron Microscopy Applied to High Resolution Freeze-Etch Replicas

1970 ◽  
Vol 28 ◽  
pp. 306-307
Author(s):  
L. Andrew Staehelin
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Resolution ◽  
Smooth Surfaces ◽  
Small Particles ◽  
Membrane Surfaces ◽  
Wide Acceptance ◽  
New Information ◽  
Number Of Particles ◽  
Small Holes

Freeze-etched membranes usually appear as relatively smooth surfaces covered with numerous small particles and a few small holes (Fig. 1). In 1966 Branton (1“) suggested that these surfaces represent split inner mem¬brane faces and not true external membrane surfaces. His theory has now gained wide acceptance partly due to new information obtained from double replicas of freeze-cleaved specimens (2,3) and from freeze-etch experi¬ments with surface labeled membranes (4). While theses studies have fur¬ther substantiated the basic idea of membrane splitting and have shown clearly which membrane faces are complementary to each other, they have left the question open, why the replicated membrane faces usually exhibit con¬siderably fewer holes than particles. According to Branton's theory the number of holes should on the average equal the number of particles. The absence of these holes can be explained in either of two ways: a) it is possible that no holes are formed during the cleaving process e.g. due to plastic deformation (5); b) holes may arise during the cleaving process but remain undetected because of inadequate replication and microscope techniques.

Structure and Hardness of Cryorolled and Heat-Treated 2xxx Aluminum Alloy

2010 ◽  
Vol 667-669 ◽  
pp. 925-930
Author(s):  
S.V. Krymskiy ◽  
Elena Avtokratova ◽  
M.V. Markushev ◽  
Maxim Yu. Murashkin ◽  
O.S. Sitdikov
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
Coarse Grained ◽  
Aging Response ◽  
Heat Treated ◽  
Aluminum Solid Solution ◽  
A Cell

The effects of severe plastic deformation (SPD) by isothermal rolling at the temperature of liquid nitrogen combined with prior- and post-SPD heat treatment, on microstructure and hardness of Al-4.4%Cu-1.4%Mg-0.7%Mn (D16) alloy were investigated. It was found no nanostructuring even after straining to 75%. Сryodeformation leads to microshear banding and processing the high-density dislocation substructures with a cell size of ~ 100-200 nm. Such a structure remains almost stable under 1 hr annealing up to 200oC and with further temperature increase initially transforms to bimodal with a small fraction of nanograins and then to uniform coarse grained one. It is found the change in the alloy post–SPD aging response leading to more active decomposition of the preliminary supersaturated aluminum solid solution, and to the alloy extra hardening under aging with shorter times and at lower temperatures compared to T6 temper.

Sign in / Sign up

Export Citation Format

Share Document