Microstructural Evolution during Annealing of 5052 Al Alloy Deformed at Cryogenic Temperature

2007 ◽  
Vol 124-126 ◽  
pp. 1393-1396 ◽  
Author(s):  
Ui Gu Gang ◽  
Yong Sin Lee ◽  
Kyung Tae Park ◽  
Won Jong Nam
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Cryogenic Temperature ◽  
Volume Fraction ◽  
Uniform Elongation ◽  
Good Combination ◽  
Al Alloy ◽  
Bimodal Microstructure ◽  
Coarse Grains ◽  
Bimodal Grain Size

The activation energy for recovery and recrystallization was calculated using DSC data. The annealing below 250°C resulted in the bimodal grain size distribution, while that above 300°C resulted in the uniform distribution of coarse grains. The formation of a bimodal microstructure would be responsible for the good combination of uniform elongation and tensile strength. Additionally, the little variation of hardness for different annealing time at 300°C also indicated that mechanical properties of deformed and annealed 5052 Al alloy were significantly influenced by the volume fraction of recrystallized grains rather than the coarsening of recrystallized grains.

scholarly journals Annealing effect on microstructure and mechanical properties of Cu-Al alloy subjected to Cryo-ECAP

2018 ◽  
Vol 8 (1) ◽  
pp. 377-381
Author(s):  
Kun Xia Wei ◽  
Sheng Long Wang ◽  
Wei Wei ◽  
Qing Bo Du ◽  
Igor V. Alexandrov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cryogenic Temperature ◽  
Uniform Elongation ◽  
Annealing Effect ◽  
Al Alloy ◽  
Angular Pressing ◽  
Microstructure And Mechanical Properties ◽  
Annealing Twins ◽  
Before And After ◽  
Liquid Nitrogen Cooling

Abstract Cu-7%Al alloy subjected to equal channel angular pressing at cryogenic temperature with liquid nitrogen cooling (Cryo-ECAP)was treated by annealing. The microstructure and mechanical properties of Cu-7%Al alloy before and after annealing were investigated. It shows that a large number of annealing twins formed in Cu-7%Al alloy subjected to Cryo-ECAP. After 300∘C and 0.5 h annealing in Cu-7%Al alloy processed by Cryo-ECAP, tensile strength and uniform elongation was increased up to 644 MPa and 7.6% respectively. The enhanced mechanical properties of Cu-7%Al alloy after annealing is attributed to the high density nanoscale twins.

Microstructures and Mechanical Properties of AZ61 Mg Alloy Processed by Equal Channel Angular Pressing

2012 ◽  
Vol 468-471 ◽  
pp. 2124-2127 ◽  
Author(s):  
Shao Feng Zeng ◽  
Kai Huai Yang ◽  
Wen Zhe Chen
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Uniform Elongation ◽  
Considerable Decrease ◽  
Angular Pressing ◽  
Az61 Magnesium Alloy ◽  
Average Grain Size ◽  
Microstructures And Mechanical Properties ◽  
Bimodal Grain Size

Equal channel angular pressing (ECAP) was applied to a commercial AZ61 magnesium alloy for up to 8 passes at temperatures as low as 473K. Microstructures and mechanical properties of as-received and ECAP deformed samples were investigated. The microstructure was initially not uniform with a “bimodal” grain size distribution but became increasingly homogeneous with further ECAP passes and the average grain size was considerably reduced from over 26 μm to below 5 μm. The ultimate tensile strength (UTS) decreases clearly after one pass, but increases significantly up to two passes, and then continuously slowly decreases up to six passes, and again increases slightly up to eight passes. In contrast, the uniform elongation increased significantly up to 3 passes, followed by considerable decrease up to 8 passes. These observations may be attributed to combined effects of grain refinement and texture development.

scholarly journals Enhanced Mechanical Properties of Mg-6Sn-3Al-1Zn Alloy with Bimodal Grain Size Disturbed in the Microstructure Uniformly through Changing the Rolling Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Fuan Wei ◽  
Jinhui Wang ◽  
Ping Li ◽  
Bo Shi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Volume Fraction ◽  
Rolling Temperature ◽  
Average Grain Size ◽  
Small Grains ◽  
Mg2sn Phase ◽  
Average Size ◽  
Bimodal Grain Size

The mechanical properties of Mg-6Sn-3Al-1Zn alloy were enhanced with bimodal grain size disturbed in the microstructure uniformly; the Mg-6Sn-3Al-1Zn alloys were rolled with 60% thickness reduction at different rolling temperatures. The results have shown that the Mg-6Sn-3Al-1Zn alloys are composed of Mg2Sn phase and α-Mg matrix phase. When the rolling temperature was less than or equal to 400°C, with the rolling temperature increasing, the average size and volume fraction of Mg2Sn phase and the average grain size of small grains remained unchanged, the average grain size of large grains decreased, the volume fraction of small grains increased, and the yield strength of the alloy increased. When the rolling temperature reached 450°C, the average size and volume fraction of Mg2Sn phase and the average grain size of large grains increased, and the volume fraction of small grains and the yield strength of the alloy decreased. The elongation increased with the rolling temperature increasing, but the change trend of hardness was just opposite. When the alloy was rolled at 400°C, the average sizes of small grains, large grains, and Mg2Sn phases were 3.66 μm, 9.24 μm, and 19.5 μm, respectively. The volume fractions of small grains, large grains, and Mg2Sn phases were 18.6%, 77.6%, and 3.8%, respectively. And the tensile properties reached the optimum; for example, the tensile strength, yield strength, elongation, and Vickers hardness were 361 MPa, 289.5 MPa, 20.5%, and 76.3 HV, respectively.

Change of Mechanical Properties of High Strength Line Pipe by Thermal Coating Treatment

2005 ◽  
Author(s):  
Yasuhiro Shinohara ◽  
Takuya Hara ◽  
Eiji Tsuru ◽  
Hitoshi Asahi ◽  
Yoshio Terada ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Uniform Elongation ◽  
High Strength ◽  
Secondary Phase ◽  
Longitudinal Direction ◽  
Dual Phase ◽  
Line Pipe ◽  
Thermal Coating ◽  
Production Conditions

In strain-based design, the overmatch condition in the girth weld portion primarily must be maintained. The pipes may also be required to have a low yield to tensile (Y/T) ratio and a high uniform elongation (U.EL) in the longitudinal direction to achieve a high compressive buckling strain. However, change in the mechanical properties by heating during coating treatment has not been paid attention so much. Furthermore, how much the mechanical properties change is affected by production conditions is unclear. This study aims to clarify firstly the relation between the mechanical properties (Y/T ratio, U.EL etc.) and the microstructure and secondly the change in mechanical properties by thermal coating treatment. The Y/T ratio and U.EL are affected by the volume fraction of ferrite and the secondary phase, which are changed by thermomechanical control processing (TMCP) conditions. For example, use of dual phase microstructure is very effective for decreasing the Y/T ratio and increasing the U.EL as the pipe. On the other hand, yield strength (YS) rises and the U.EL does not change after coating. The increase in the YS after coating is influenced by the microstructure and TMCP conditions. Resultantly, dependence of the Y/T ratio on the microstructure and TMCP conditions is reduced for line pipes after thermal coating treatment.

scholarly journals Study on the Relationship between High Temperature Mechanical Properties and Precipitates Evolution of 7085 Al Alloy after Long Time Thermal Exposures

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1483
Author(s):  
Jinxin Zang ◽  
Pan Dai ◽  
Yanqing Yang ◽  
Shuai Liu ◽  
Bin Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Tensile Properties ◽  
Volume Fraction ◽  
Al Alloy ◽  
Strengthening Effect ◽  
Nano Scale ◽  
High Temperature Mechanical Properties ◽  
The Relationship

The requirement for 7085 Al alloy as large airframe parts has been increasing due to its low quenching sensitivity and high strength. However, the relationship between high temperature mechanical properties and the evolution of precipitates in hot environments is still unclear. In this work, thermal exposure followed by tensile tests were conducted on the 7085 Al alloy at various temperatures (100 °C, 125 °C, 150 °C and 175 °C). Variations of hardness, electrical conductivity and tensile properties were investigated. The evolution of the nano scale precipitates was also quantitatively characterized by transmission electron microscopy (TEM). The results show that the hardness and electrical conductivity of the alloy are more sensitive to the temperature than to the time. The strength decreases continuously with the increase of temperature due to the transformation from η′ to η phase during the process. Furthermore, the main η phase in the alloy transformed from V3 and V4 to V1 and V2 variants when the temperature was 125 °C. Additionally, with increasing the temperature, the average precipitate radius increased, meanwhile the volume fraction and number density of the precipitates decreased. The strengthening effect of nano scale precipitates on tensile properties of the alloy was calculated and analyzed.

Mechanical Properties and Microstructures of 5052 Al Alloy Processed by Asymmetric Cryorolling

2016 ◽  
Vol 850 ◽  
pp. 823-828 ◽  
Author(s):  
Jin Tao Shi ◽  
Long Gang Hou ◽  
Cun Qiang Ma ◽  
Jin Rong Zuo ◽  
Hua Cui ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Grain Refinement ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Velocity Ratio ◽  
Experimental Results ◽  
Al Alloy ◽  
Cryogenic Temperatures

Aluminum alloy sheets were asymmetrically rolled at room and cryogenic temperatures by imposing different velocity ratios of 1~1.5 between the upper and bottom rolls. After rolling, the stress-strain curves, microhardness as well as the microstructures of the rolled samples were characterized and analyzed. The experimental results showed that the asymmetric cryorolling could improve the grain refinement and offered (~12%) higher room temperature tensile strength than that processed by symmetrical rolling with velocity ration of 1.0 (~280 MPa). However, at cryogenic temperature, the strength of asymmetrically cryorolling sheet (with velocity ratio of 1.5) was 5.1%, which is less than that processed by symmetrical rolling.

Role of Equiaxed Primary Alpha (α׳) and Mechanical Properties of Ti-6Al-4V Alloy

2012 ◽  
Vol 510-511 ◽  
pp. 420-428
Author(s):  
A. Ahmad ◽  
A. Ali ◽  
G.H. Awan ◽  
K.M. Ghauri ◽  
R. Aslam
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Volume Fraction ◽  
Lamellar Microstructure ◽  
Phase Region ◽  
Bimodal Microstructure ◽  
Two Phase ◽  
Primary Alpha ◽  
Fully Lamellar

The paper presents the role of equiaxed α׳ in the bimodal microstructure to attain an optimal combination of ductility and strength. The study revealed that the production of bimodal microstructure and volume fraction of equiaxed α׳ were reliant on the forging temperature and subsequent heat treatment. The Ti-6Al-4V alloy was forged in the two phase region and different heat treatment cycles were employed to get the desired bimodal microstructure and thus the combination of strength and ductility. The mechanical properties of fully lamellar microstructure were compared with bimodal microstructure containing equiaxed α׳. The experimental results showed that the amount of equiaxed α׳ in the bimodal microstructure was critical for achieving a well-balanced profile of mechanical properties.

A Comparative Study on Mechanical Properties of Al 7075 Alloy Processed by Rolling at Cryogenic Temperature and Room Temperature

2008 ◽  
Vol 584-586 ◽  
pp. 734-740 ◽  
Author(s):  
Sushanta Kumar Panigrahi ◽  
R. Jayaganthan
Keyword(s):  
Mechanical Properties ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Microstructural Characterization ◽  
Liquid Nitrogen Temperature ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Al Alloy ◽  
Al 7075 ◽  
7075 Alloy

The mechanical properties and microstructural characteristics of a precipitation hardenable Al 7075 alloy subjected to rolling at liquid nitrogen temperature and room temperature are reported in this present work. The Al 7075 alloy was severely rolled at cryogenic temperature and room temperature and its mechanical properties were studied by using tensile tests and hardness. The microstructural characterization of Al 7075 alloy were made using SEM/EBSD, TEM and DSC. The cryorolled Al 7075 alloys have shown improved mechanical properties as compared to the room temperature rolled Al alloy. The cryorolled Al alloy after 90% thickness reduction exhibits ultrafine grain structure as observed from its TEM micrographs. It is observed that the strength and hardness of the cryorolled materials (CR) at different percentage of thickness reductions are higher as compared to the room temperature rolled (RTR) materials at the same strain due to suppression of dynamic recovery and accumulation of higher dislocations density in the CR materials.

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