Effect of Artificial Aging on Microstructures and Mechanical Properties of Extruded Mg Alloy ZK60

2014 ◽  
Vol 697 ◽  
pp. 72-75
Author(s):  
De Liang Yin ◽  
Jian Qiao ◽  
Hong Liang Cui
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Aging Time ◽  
Artificial Aging ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Tensile Yield Strength ◽  
Uniaxial Tensile ◽  
Fracture Elongation ◽  
Strength And Ductility

An extruded ZK60 magnesium alloy was subjected to artificial aging at 180 oC for an investigation of the effect of aging time on its precipitation behavior and mechanical properties. Uniaxial tensile tests were conducted to obtain the mechanical properties. Optical microscopy and transmission electron microscopy (TEM) were employed to observe microstructure change before and after aging treatment. It is shown that, both tensile yield strength and ultimate tensile strength increases with aging time. The fracture elongation after aging for 20 h reaches up to 21.0%, and the yield strength increases to 269.5 MPa, 19.4% higher than that of extruded specimens (un-aged), showing a good match of strength and ductility. Three newly-formed precipitates were observed after aging for over 20 h, among which particulate and dispersive precipitates should be responsible for the good combination of strength and ductility.

Correlation among Microstructure, Texture, and Properties along the Thickness Direction in As-Hot-Rolled and As-Solution-Quenched Al7055 Thick Plates

2021 ◽  
Vol 1026 ◽  
pp. 65-73
Author(s):  
Kai Zhu ◽  
Hong Wei Yan
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Tensile Tests ◽  
Rolled Plate ◽  
Uniaxial Tensile ◽  
Thickness Direction ◽  
Electron Backscattered Diffraction ◽  
Thick Plates ◽  
Aluminum Plates ◽  
Hot Rolled

Both microstructure inhomogeneity and mechanical property diversity along the thickness direction in rolled thick aluminum plates have been considered to have a remarkable impact on the performance and properties of the products made from the plates. In this study, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) characterizations of microstructure and texture types along the thickness directions of Al7055 thick plate specimens prepared using two conditions, hot-rolling and solution-quenching, were performed. To examine the mechanical properties, uniaxial tensile tests were also carried out on specimens machined from both types of thick plates, using a layered strategy along the thickness direction. The results indicate that both the microstructure and mechanical properties are inhomogeneous under the two conditions. Furthermore, it is evident that there is a hereditary relationship between the mechanical properties of the two plates—areas with higher yield strength in the as-hot-rolled plate correspond to areas with the higher yield strength in the as-solution-quenched plate

Functional Gradation in Precipitation Hardenable AA7075 Alloy by Differential Cooling Strategies

2021 ◽  
Vol 883 ◽  
pp. 159-166
Author(s):  
Emad Scharifi ◽  
Moritz Roscher ◽  
Steffen Lotz ◽  
Ursula Weidig ◽  
Eric Jägle ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Particle ◽  
Hot Stamping ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Material Strength ◽  
Second Phase ◽  
Contrast Imaging ◽  
Forming Tools

Inspired by steel forming strategies, this study focuses on the effect of differential cooling on mechanical properties and precipitation kinetics during hot stamping of high strength AA7075 alloy. For this aim, different forming strategies were performed using segmented and differentially heated forming tools to provide locally tailored microstructures. Upon processing, uniaxial tensile tests and hardness measurements were used to characterize the mechanical properties after the aging treatment. Microstructure investigations were conducted to examine the strengthening mechanisms using the electron channeling contrast imaging (ECCI) technique in a scanning electron microscope (SEM). Based on the obtained results, it can be deduced that the tool temperatures play a key role in influencing the mechanical properties. Lower tool temperatures result in higher material strength and higher tool temperatures in lower mechanical properties. By changing the cooling rate with the use of differently heated forming tools, the mechanical properties can be controlled. Microstructure investigations revealed the formation of very fine and homogeneously distributed particles at cooled zones, which were associated with elevated mechanical properties due to the suppression of second phase particle formation during cooling. In contrast, coarse particles were observed at lower cooling rates, explaining the lower material strength found in these zones.

scholarly journals Achieving High Yield Strength and Ductility in As-Extruded Mg-0.5Sr Alloy by High Mn–Alloying

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4176
Author(s):  
Shibo Zhou ◽  
Xiongjiangchuan He ◽  
Peng Peng ◽  
Tingting Liu ◽  
Guangmin Sheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Tensile Yield Strength ◽  
High Yield ◽  
Compressive Yield Strength ◽  
High Yield Strength ◽  
Pinning Effect ◽  
Small Grains ◽  
Strength And Ductility

The effect of Mn on the microstructure and mechanical properties of as-extruded Mg-0.5Sr alloy were discussed in this work. The results showed that high Mn alloying (2 wt.%) could significantly improve the mechanical properties of the alloys, namely, the tensile and compressive yield strength. The grain size of as-extruded Mg-0.5Sr alloys significantly was refined from 2.78 μm to 1.15 μm due to the pinning effect by fine α-Mn precipitates during the extrusion. Moreover, it also showed that the tensile yield strength and the compressive yield strength of Mg-0.5Sr-2Mn alloy were 32 and 40 percent age higher than those of Mg-0.5Sr alloy, respectively. Moreover, the strain hardening behaviors of the Mg-0.5Sr-2Mn alloy were discussed, which proved that a large number of small grains and texture have an important role in improving mechanical properties.

scholarly journals Microstructural Evolution and Mechanical Behavior of an Al-6061 Alloy Processed by Repetitive Corrugation and Straightening

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 489
Author(s):  
Sergio Elizalde ◽  
Marco Ezequiel ◽  
Ignacio A. Figueroa ◽  
José M. Cabrera ◽  
Chedly Braham ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Yield Strength ◽  
Electron Backscatter Diffraction ◽  
Tensile Tests ◽  
Die Design ◽  
Uniaxial Tensile ◽  
Hardness Distribution ◽  
Heterogeneous Distribution ◽  
Al 6061

The repetitive corrugation and straightening process is a severe plastic deformation technique that is particularly suited to process metallic sheets. With this technique, it is possible to develop nano/ultrafine-grained structured materials, and therefore, to improve some mechanical properties such as the yield strength, ultimate tensile strength, and fatigue lifetime. In this study, an Al-6061 alloy was subjected to the repetitive corrugation and straightening process. A new corrugation die design was proposed in order to promote a heterogeneous deformation into the metallic sheet. The evolution of the mechanical properties and microstructure obtained by electron backscatter diffraction of the alloy showed a heterogeneous distribution in the grain size at the initial cycles of the repetitive corrugation and straightening process. Uniaxial tensile tests showed a significant increase in yield strength as the number of repetitive corrugation and straightening passes increased. The distribution of the plastic deformation was correlated with the hardness distribution on the surface. The hardness distribution map matched well with the heterogeneous distribution of the plastic deformation obtained by finite element simulation. A maximum average hardness (147 HV) and yield strength (385 MPa) was obtained for two repetitive corrugation and straightening cycles sample.

Effect of Aging on Microstructure and Performance after Superplastic Deformation of Fine Grained 1420 Al-Li Alloy

2014 ◽  
Vol 936 ◽  
pp. 1647-1652
Author(s):  
Yan Ling Zhang ◽  
Hong Liang Hou ◽  
Yao Qi Wang
Keyword(s):  
Mechanical Properties ◽  
Artificial Aging ◽  
Superplastic Forming ◽  
Tensile Tests ◽  
Strengthening Mechanism ◽  
Fine Grained ◽  
And Performance ◽  
Relationship Of ◽  
Microstructure And Performance ◽  
Strength And Ductility

Superplastic forming (SPF) is an important process for forming fine grained 1420 Al-Li alloy. However, the mechanical properties will be decreased after deforming at high temperature. How to obtain the optimize relationship of strength and ductility after SPF is one of the key problems for the process. In this paper, a set of artificial aging tests including single and two-step aging were carried out, which are the typical strengthening process for Al-Li alloy. Based on experimental results, strength and elongation were studied by means of tensile tests at room temperature, and the effect of aging processes on mechanical properties was analyzed. Finally, the microstructures fore and after aging were examined by OM and TEM, and the strengthening mechanism of 1420 Al-Li alloy was further studied. It is found that artificial aging especially two-step aging can increase mechanical properties of post-SPF material obviously, and δ (Al3Li) is the primary strengthening phase.

scholarly journals Effect of the δ Phase on the Tensile Properties of a Nickel-Based Superalloy

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1153 ◽  
Author(s):  
Qiang Zhu ◽  
Gang Chen ◽  
Chuanjie Wang ◽  
Lukuan Cheng ◽  
Heyong Qin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Aging Time ◽  
Aging Treatment ◽  
Single Mode ◽  
Tensile Tests ◽  
Fracture Site ◽  
Precipitation Method ◽  
Inhomogeneous Strain ◽  
Δ Phase

Nickel-based superalloys are widely used in aerospace and other fields due to their excellent properties. In this study, the aging treatment and tensile tests of a GH4169 alloy were carried out. The effects of the δ phase on the alloy’s mechanical properties and fracture behavior were studied. The results showed that the appearance of the δ phase changed from a short rod shape to a needle shape with an increase in aging time. The precipitation method changed from a single mode of precipitation along the grain boundary to two modes of precipitation along the grain boundary and direct precipitation inside the grain. The yield strength and ultimate tensile strength of the alloy first increased and then decreased with an increase in aging time and were related with the microstructure of the δ phase. The similar Widmanstatten structure was not conducive to the mechanical properties of the alloy. The distribution of the δ phase led to the generation of inhomogeneous strain and limited the surface roughening during plastic deformation. The voids initiated at the interface between the δ phase and the matrix γ phase or directly from the δ phase fracture site.

scholarly journals Mechanical Properties and Microstructure of a Duplex Nanostructure

2010 ◽  
Vol 667-669 ◽  
pp. 973-978
Author(s):  
L. Chen ◽  
Ping Jiang ◽  
Xiao Lei Wu ◽  
Mu Xin Yang ◽  
Chang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Yield Strength ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Angular Pressing ◽  
Elongation To Failure

The nanostructure was obtained in a duplex stainless steel (DSS) by means of equal channel angular pressing. The mechanical properties were characterized by uniaxial tensile tests, while the microstructure was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was shown that the yield strength in a deformed nanostructure increased significantly from 402 MPa to 1461 MPa as compared to its coarse-grained counterpart. In contrast, the uniform elongation decreased significant to only 2% together with elongation to failure of 9.8%, much lower than those of 25.4% and 42.6%. After annealing at 700°C for 10 minute, however, uniform elongation increases to 5.3% with the yield strength of 1200 MPa. TEM observation exhibited that deformation twins prevail in the austenite phase whereas the dislocations of high density present in ferrite. The plastic behavior in both phases was analyzed based on the deformation twinning and the presence of dislocation. Finally, the effect of the microstructure on mechanical properties was discussed.

scholarly journals Effect of Aging and Deformation Treatments on Mechanical Properties of Aluminum AA-6063

2021 ◽  
Vol 9 (6) ◽  
pp. 158-168
Author(s):  
Alcántara Alza Víctor
Keyword(s):  
Mechanical Properties ◽  
Aging Temperature ◽  
Artificial Aging ◽  
Aging Treatment ◽  
Tensile Tests ◽  
Deformation Degree ◽  
Β Phase ◽  
Eds Analysis ◽  
Complete Recrystallization ◽  
Hardness Values

How the parameters of artificial aging heat treatments, in AA 6063 aluminum samples, previously solubilized and deformed in cold, influence on the mechanical properties of hardness and traction was investigated. The experiments followed the sequence: First, the solubilization treatment was carried out for 2h using prismatic specimens of 10mm thickness; then the samples were cold deformed with area reductions: 30% -60% -80%. Finally, the aging treatment was carried out on all samples, using temperatures: 150-250-350-450 °C, and holding times: 1-10-30-60-90-120 min. After aging the samples were machined according to the standards. The hardness was measured on the Vickers scale (HV) and the tensile tests followed the ASTM E 8M-95ª standard. Microscopy was performed at the optical and Electronic SEM level, complemented with an EDS analysis. It was found that the highest hardness values occur at 150 °C. The yield point YS increases as decreasing aging temperature, and decreases whith increasing deformation degree. The mechanical strength UTS increases as decreasing temperature and increasing whith deformation degree. Regarding the mechanical properties of traction, the optimal condition is found for the samples deformed at 80% and aged at 250 °C, presenting a (UTS) of 193 MPa, and 15% elongation. The samples with 80% reduction, aged at 450 °C for 120 min are those with the best recrystallization index. It would take a time greater than 120 min for the grains to thicken and the precipitates completely disappear to reach complete recrystallization. EDS analysis indicates the presence of Mg2Si precipitates and the β phase.

scholarly journals Comparative Study of Two Aging Treatments on Microstructure and Mechanical Properties of an Ultra-Fine Grained Mg-10Y-6Gd-1.5Zn-0.5Zr Alloy

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 658 ◽  
Author(s):  
Huan Liu ◽  
He Huang ◽  
Ce Wang ◽  
Jia Ju ◽  
Jiapeng Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloys ◽  
Aging Treatment ◽  
High Strength ◽  
Tensile Tests ◽  
Aged Alloy ◽  
Fine Grained ◽  
Peak Aging ◽  
Peak Aged ◽  
Strength And Ductility

Developing high strength and high ductility magnesium alloys is an important issue for weight-reduction applications. In this work, we explored the feasibility of manipulating nanosized precipitates on LPSO-contained (long period stacking ordered phase) ultra-fine grained (UFG) magnesium alloy to obtain simultaneously improved strength and ductility. The effect of two aging treatments on microstructures and mechanical properties of an UFG Mg-10Y-6Gd-1.5Zn-0.5Zr alloy was systematically investigated and compared by a series of microstructure characterization techniques and tensile test. The results showed that nano γ’’ precipitates were successfully introduced in T5 peak aged alloy with no obvious increase in grain size. While T6 peak aging treatment stimulated the growth of α-Mg grains to 4.3 μm (fine grained, FG), together with the precipitation of γ’’ precipitates. Tensile tests revealed that both aging treatments remarkably improved the strengths but impaired the ductility slightly. The T5 peak aged alloy exhibited the optimum mechanical properties with ultimate strength of 431 MPa and elongation of 13.5%. This work provided a novel strategy to simultaneously improve the strength and ductility of magnesium alloys by integrating the intense precipitation strengthening with ductile LPSO-contained UFG/FG microstructure.

Effects of the Aging Time and Temperature on the Microstructures and Mechanical Properties of 6082 Aluminum Alloy Extrusions

2013 ◽  
Vol 652-654 ◽  
pp. 1035-1042
Author(s):  
Tao Wu ◽  
Xian Fei Ding ◽  
Jing Sun ◽  
Wei Dong Zhang ◽  
Dong Bai Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Aging Time ◽  
Tensile Elongation ◽  
Aging Treatment ◽  
Longitudinal Direction ◽  
Tensile Tests ◽  
Main Task ◽  
6082 Aluminum Alloy ◽  
Effects Of Aging

The main task of this work was to study the effects of aging time and aging temperature on the microstructure and mechanical properties of 6082 aluminum alloy extrusions. Artificial aging was performed on the alloy extrusions at the temperatures of 150, 175 and 200 °C for the aging times of 4, 8 and 12 h. The microstructure evolution of the aluminum alloy extrusions with increase of the aging time and temperature was investigated by Field Emission Scanning Electron Microscope (FESEM). For the purpose of how the aging process affected the mechanical properties, tensile tests were performed. The results showed that the optimum aging treatment was 175 °C/4 h. Under this condition, the tensile strength (Rm) and the yield strength (Rp) in the longitudinal direction of the extrusions reached the maximum value more than 350MPa and 320MPa, respectively, and the tensile elongation (A) was more than 15%.

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