Microstructure Evolution and Microhardness of 7075 Aluminum Alloy during Heat Treatment by Considering Hot Deformation History

2013 ◽  
Vol 699 ◽  
pp. 851-858 ◽  
Author(s):  
Zhi Chao Sun ◽  
Ji Lun Yin ◽  
He Yang
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Strain Rate ◽  
Aging Process ◽  
Static Recrystallization ◽  
Heat Treatments ◽  
7075 Aluminum Alloy ◽  
Deformation History ◽  
Recrystallized Grain Size

In this paper, two heat treatment routes have been carried out on a set of hot compressed 7075 aluminum alloy samples under different deforming conditions. By considering the hot deformation history the law of 7075 aluminum alloy’s microstructure evolution during these two heat treatments was studied and the microhardness was discussed. The results show that: (1) Static recrystallization in 7075 aluminum alloy was discovered during these two heat treatments (solid solution (465°C/40min) +T6 aging (120°C/24h) and solid solution (465°C/40min) + T73 aging (107°C/7h+177°C/7h)), its driving force was from stored energy which was not released in the previous thermal deformation process. Formation of recrystallized grain was due to subgrain merger mechanism. The static recrystallization became more remarkable as the hot deforming temperature decreasing. (2) The effects of strain rate on the statically recrystallized grain size of 7075 aluminum alloy were opposite under different deformation temperatures. Deformed at 450°C, during these two heat treatments the recrystallized grain size became smaller as the strain rate increasing. While deformed at 350°C, during solid solution+T73 aging treatment the recrystallized grain size increased as the strain rate increasing. (3) Under the same deformation conditions a difference existed in the microstructure of 7075 aluminum alloy after solid solution +T6 aging and solid solution + T73 aging, which was mainly due to different precipitated phases in the aging process. (4) Both two heat treatments can raise the microhardness of 7075 aluminum alloy remarkably. The hardness of 7075 aluminum alloy after solid solution+T73 aging was lower than that after solid solution+T6 aging, the main reason was the precipitated small  phase in the first stage of the T73 aging coarsen in the second stage of high-temperature aging process.

Physical Simulation of Dynamic Recrystallization Behavior of 7050 Aluminum Alloy

2008 ◽  
Vol 575-578 ◽  
pp. 1083-1085
Author(s):  
You Ping Yi ◽  
Yan Shi
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Physical Simulation ◽  
Simulation Method ◽  
Strain Rate Range ◽  
Compression Tests ◽  
7050 Aluminum Alloy ◽  
Recrystallized Grain Size

This work aims to investigate the influence of hot deformation on dynamic recrystallization(DRX) behavior of 7050 aluminum alloy by means of physical simulation method. The hot compression tests were carried out on Gleeble 1500 machine in temperature range of 250-450°C and strain rate range of 0.01–10 s-1. Transmission electronic microscopy (TEM) was employed to observe and analyze the microstructure and DRX behavior in different deformation conditions. The results show that the effects of deformation temperature and strain rate on microstructural evolution of the alloy are remarkable. When temperature is lower than 350°C, only the dynamical recovery( DRV) occurs and typical sub-grains appear. In the range of 350-400°C, the incomplete DRX occurs and the recrystallized grain size increases with increasing temperature. The complete DRX occurs at 450°C and the fine equiaxied grains with high-angle boundaries develop resultantly. The DRX grain size increases as strain rate decreases. The desirable microstructure and properties can be obtained by optimizing the forging process parameters.

High Strain Rate Superplasticity in a Zr and Sc Modified 7075 Aluminum Alloy Produced by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 164-169 ◽  
Author(s):  
Krystof Turba ◽  
Premysl Malek ◽  
Edgar F. Rauch ◽  
Miroslav Cieslar
Keyword(s):  
Aluminum Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Rate Sensitivity ◽  
7075 Aluminum Alloy ◽  
Fine Grained ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Elongation To Failure

Equal-channel angular pressing (ECAP) at 443 K was used to introduce an ultra-fine grained (UFG) microstructure to a Zr and Sc modified 7075 aluminum alloy. Using the methods of TEM and EBSD, an average grain size of 0.6 1m was recorded after the pressing. The UFG microstructure remained very stable up to the temperature of 723 K, where the material exhibited high strain rate superplasticity (HSRSP) with elongations to failure of 610 % and 410 % at initial strain rates of 6.4 x 10-2 s-1 and 1 x 10-1 s-1, respectively. A strain rate sensitivity parameter m in the vicinity of 0.45 was observed at temperatures as high as 773 K. At this temperature, the material still reached an elongation to failure of 430 % at 2 x 10-2 s-1. These results confirm the stabilizing effect of the Zr and Sc additions on the UFG microstructure in a 7XXX series aluminum alloy produced by severe plastic deformation.

The Effect of Heat Treatments and Nickel Additive on The Microstructure and Hardness of 7075 Aluminum Alloy

2019 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
Mahmoud Alasad ◽  
Mohamad Yahya Nefawy
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Artificial Aging ◽  
Heat Treatments ◽  
7075 Aluminum Alloy ◽  
Nickel Additive

The aluminum alloys of the 7xxx series consist of Al with Zn mainly, Mg and Cu. 7xxx aluminum alloys has high mechanical properties making it distinct from other aluminum alloys. In this paper, we examine the effect of adding Nickel and heat treatments on the microstructure and hardness of the 7075 aluminum alloy. Were we added different percentages of nickel [0.1, 0.5, 1] wt% to 7075 Aluminum alloy, and applied various heat treatments (artificial aging T6 and Retrogression and re-aging RRA) on the 7075 alloys that Containing nickel. By applying RRA treatment, we obtained better results than the results obtained by applying T6 treatment, and we obtained the high values of hardness and a smoother microstructure for the studied alloys by the addition of (0.5 wt%) nickel to alloy 7075.

Effect of In Situ TiB2 Particles on the Grain Size and Mechanical Properties of 7075 Aluminum Alloy

2021 ◽  
Vol 1035 ◽  
pp. 102-107
Author(s):  
Shao Ming Ma ◽  
Chuan Liu Wang ◽  
Yun Lin Fan
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Aluminum Alloy ◽  
High Strength ◽  
Light Weight ◽  
7075 Aluminum Alloy ◽  
Directional Drilling ◽  
High Strength Aluminum Alloy ◽  
Drill Pipes

Light-weight and high-strength aluminum alloy drill pipes are potential and promising to replace traditional steel drill pipes. In this study, the grain size and mechanical properties of aluminum alloy drilling pipe materials reinforced by in-situ TiB2 particles were studied. The results showed when reinforced by in-situ TiB2 particles the grain size of aluminum alloy materials was refined from 155 m to 57 m and ultimate tensile strength was increased from 590 MPa to 720 MPa. Besides, the results also indicated that the friction coefficient was reduced from 0.99 to 0.50 and thus the abrasion resistance of 7075 aluminum alloy was enhanced by 34 %. This study provided theoretical basis for the application of light-weight and high-strength aluminum alloy drill pipes in directional drilling and ultra-deep wells.

Modeling the Hot Deformation Behavior of 1565ch Aluminum Alloy

2016 ◽  
Vol 684 ◽  
pp. 35-41 ◽  
Author(s):  
S.V. Rushchits ◽  
E.V. Aryshensky ◽  
S.M. Sosedkov ◽  
A.M. Akhmed'yanov
Keyword(s):  
Aluminum Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Static Recrystallization ◽  
Strain Rates ◽  
Strain Resistance ◽  
Hot Deformation Behavior ◽  
Zirconium Addition

The deformation behavior of 1565ch alloy under the plane-strain conditions in the temperature range of 350–490 оС and strain rates range of 0,1–10 s-1 is studied. The expression for steady flow stress as the functions of temperature of deformation and strain rate is obtained. It is established that 1565ch alloy with zirconium addition shows higher strain resistance and less tendency to dynamic and static recrystallization than AMg6.

An Investigation of Cavitation in the Tensile Testing of a Spray-Cast Aluminum Alloy Processed by ECAP

2006 ◽  
Vol 503-504 ◽  
pp. 83-90 ◽  
Author(s):  
Megumi Kawasaki ◽  
Cheng Xu ◽  
Terence G. Langdon
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Strain Rate ◽  
Tensile Testing ◽  
Ultrafine Grain ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Angular Pressing ◽  
Cavity Development ◽  
Spray Casting

A commercial aluminum 7034 alloy, produced by spray casting and having an initial grain size of ~2.1 μm, was subjected to equal-channel angular pressing (ECAP) through six passes at 473 K. In the as-pressed condition, the microstructure was reasonably homogeneous and the grain size was reduced to an ultrafine grain size of ~0.3 μm. This alloy contains MgZn2 and Al3Zr precipitates which restrict grain growth. In tensile testing at 673 K after processing by ECAP, an elongation of >1000% was achieved at a strain rate of 1.0 × 10-2 s-1 corresponding to high strain rate superplasticity. Quantitative cavity measurements were conducted on the specimens after tensile testing for both the as-received condition and after ECAP. These measurements reveal a significant number of small cavities in the samples and especially in the sample that exhibited a very high elongation. This paper describes the morphology of cavity development in the spray-cast aluminum alloy in both the as-received and as-pressed condition.

scholarly journals The effect of garnet and muscovite on the recrystallized grain size of quartz from general shear experiments

2020 ◽  
Author(s):  
Leif Tokle ◽  
Greg Hirth ◽  
Luiz Morales ◽  
Holger Stunitz
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Shear Strain ◽  
Shear Strain Rate ◽  
Strain Partitioning ◽  
Secondary Phases ◽  
Volume Percent ◽  
Stress Concentrations ◽  
Bulk Stress ◽  
Recrystallized Grain Size

<p>To investigate the role of strong and weak secondary phases on the recrystallized grain size of quartz, we performed grain size analyses on quenched samples from general shear experiments on quartz-garnet and quartz-muscovite mixtures. Six general shear experiments were conducted in the Griggs apparatus; three with mixtures of quartz-garnet (vol.% garnet 5, 15, 30) and three with mixtures of quartz-muscovite (vol.% muscovite 5, 10, 25). The starting powders for both set of experiments were synthetic mixtures of quartz-muscovite or quartz-garnet with 0.1 wt.% water added. The quartz-garnet experiments were conducted at 900°C, a pressure of 1.2 GPa, and a shear strain rate of ~10<sup>-5</sup> s<sup>-1</sup>, while the quartz-muscovite experiments were conducted at 800°C, a pressure of 1.5 GPa, and a shear strain rate of ~10<sup>-5</sup> s<sup>-1</sup>. At these deformation conditions quartz is stronger than muscovite and weaker than garnet. We observed that the bulk strength of the aggregate decreases with a greater volume percent of muscovite and increases with a greater volume percent of garnet. Garnet at these conditions does not deform plastically. The presence of secondary phases within the deforming aggregate causes stress concentrations and partitioning of strain rate between the different phases relative to the measured bulk stress and strain rate. The degree of partitioning is primarily related to the rheology and volume percent of the phases. Due to the piezometric relationship between recrystallized grain size and stress, we can use the quartz recrystallized grain size to determine the local stress of quartz in the experiments and compare it to the measured bulk stress. The results from these analyses will provide new insight into the effect of strain partitioning in general and of strong and weak secondary phases on quartz rheology.</p>

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