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D L Chen - One of the best experts on this subject based on the ideXlab platform.
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detwinning and Strain Hardening of an extruded magnesium alloy during compression
Scripta Materialia, 2012Co-Authors: D Sarker, D L ChenAbstract:The plastic deformation of an extruded Mg–Al–Mn (AM30) magnesium alloy in the extrusion direction by compression can be characterized by three distinct stages. Twinning was observed in stage A with a decreasing Strain-Hardening rate. Detwinning occurred due to strong twin–dislocation interactions in stage B, which was represented by an increasing Strain-Hardening rate over an extended Strain range. Stage C with a decreasing Strain-Hardening rate was due to a reducing resistance of fewer twins to the dislocation slip.
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Strain Hardening and Strain rate sensitivity of an extruded magnesium alloy
Journal of Materials Engineering and Performance, 2008Co-Authors: D L ChenAbstract:The Strain-Hardening behavior and Strain-rate sensitivity of an extruded AZ31B magnesium alloy were determined at different Strain rates between 10−2 and 10−5 s−1 in relation to the thickness of specimens (2.5 and 4.5 mm). Both the common approach and Lindholm’s approach were used to evaluate the Strain-rate sensitivity. The yield strength (YS) and the ultimate tensile strength (UTS) increased, the ductility decreased, and the brittle fracture characteristics increased with increasing Strain rate. The thinner specimens exhibited a slightly higher UTS, lower ductility, higher Strain-Hardening exponent, and Strain-Hardening rate due to smaller grain sizes. The stage III Strain-Hardening rate linearly decreased with increasing true stress, but increased with increasing Strain rate. In comparison to the common approach, the Lindholm’s approach was observed to be more sensitive in characterizing the Strain-rate sensitivity due to larger values obtained. The thinner specimens also exhibited higher Strain-rate sensitivity. As the true Strain increased, the Strain-rate sensitivity decreased.
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Strain Hardening behavior of a friction stir welded magnesium alloy
Scripta Materialia, 2007Co-Authors: Nazia Afrin, D L Chen, Mohammad JahaziAbstract:The work Hardening properties of a friction stir welded (FSWed) magnesium alloy were evaluated using two modified equations of Hardening capacity and Strain Hardening exponent where the elastic deformation stage was excluded. Kocks–Mecking type plots were used to show different stages of Strain Hardening. The Hardening capacity of the FSWed samples was observed to be about twice that of the base alloy, while the Strain Hardening exponent of the FSWed samples was nearly threefold higher than that of the base alloy.
Xianhua Chen - One of the best experts on this subject based on the ideXlab platform.
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Strain Hardening of as extruded mg xzn x 1 2 3 and 4 wt alloys
Journal of Materials Science & Technology, 2019Co-Authors: Chaoyue Zhao, Teng Tu, Xianhua Chen, Jingfeng Wang, Andrej AtrensAbstract:The influence of Zn on the Strain Hardening of as-extruded Mg-xZn (x = 1, 2, 3 and 4 wt%) magnesium alloys was investigated using uniaxial tensile tests at 10 s at room temperature. The Strain Hardening rate, the Strain Hardening exponent and the Hardening capacity were obtained from true plastic stress-Strain curves. There were almost no second phases in the as-extruded Mg-Zn magnesium alloys. Average grain sizes of the four as-extruded alloys were about 17.8 μm. With increasing Zn content from 1 to 4 wt%, the Strain Hardening rate increased from 2850 MPa to 6810 MPa at (σ-σ) = 60 MPa, the Strain Hardening exponent n increased from 0.160 to 0.203, and the Hardening capacity, Hc increased from 1.17 to 2.34. The difference in Strain Hardening response of these Mg-Zn alloys might be mainly caused by weaker basal texture and more solute atoms in the α-Mg matrix with higher Zn content.
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Effect of Sn content on Strain Hardening behavior of as-extruded Mg-Sn alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Chaoyue Zhao, Xianhua Chen, Di ZhaoAbstract:Abstract The effects of Sn content on Strain Hardening behavior of as-extruded Mg-xSn (x = 1.3, 2.4, 3.6 and 4.7 wt%) binary alloys were investigated by uniaxial tensile tests at room temperature. Strain Hardening rate, Strain Hardening exponent and Hardening capacity were obtained from the true plastic stress-Strain curves. After hot extrusion, the as-extruded Mg-Sn alloys are mainly composed of α-Mg matrix and second phase Mg2Sn, which only exists in Mg-3Sn and Mg-4Sn. Average grain size decreases from 15.6 μm to 3.6 µm with Sn content increases from 1.3 to 4.7 wt%. The experimental results show that Sn content decreases Strain Hardening ability of as-extruded Mg-Sn alloys, but gives rise to an obvious elevation in tensile strength, yield strength and elongation of them. With increasing Sn content, Strain Hardening rate decreases from 3527 MPa to 1211 MPa at (σ-σ0.2) = 50 MPa, Strain Hardening exponent decreases from 0.21 to 0.13 and Hardening capacity decreases from 1.66 to 0.63. The variation in Strain Hardening behavior of Mg-Sn alloys with Sn content is discussed in terms of the influences of grain size and distribution of grain orientation.
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effect of heat treatment on Strain Hardening of zk60 mg alloy
Materials & Design, 2011Co-Authors: Xianhua Chen, Ai Tao Tang, Dingfei Zhang, Jingfeng Wang, Jian PengAbstract:Abstract Strain Hardening behaviors of extruded ZK60 Mg alloy under different heat treatments (T4, T5 and T6) were studied using uniaxial tensile tests at room temperature. Hardening capacity, Strain Hardening exponent as well as Strain Hardening rate curve were obtained according to true plastic stress–Strain curves. T5 and T6 treatments decrease Strain Hardening of extruded ZK60 alloy, and subsequently give rise to an obvious reduction in tensile uniform Strain. While, as-T4 treated specimen shows the strongest Strain Hardening ability among these specimens, and its Hardening capacity and Strain Hardening exponent are nearly twice those of as-T5 and T6 treated specimens. These effects were analyzed in terms of the microstructural variation and dislocation storage in ZK60 alloy.
Chaoyue Zhao - One of the best experts on this subject based on the ideXlab platform.
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Strain Hardening of as extruded mg xzn x 1 2 3 and 4 wt alloys
Journal of Materials Science & Technology, 2019Co-Authors: Chaoyue Zhao, Teng Tu, Xianhua Chen, Jingfeng Wang, Andrej AtrensAbstract:The influence of Zn on the Strain Hardening of as-extruded Mg-xZn (x = 1, 2, 3 and 4 wt%) magnesium alloys was investigated using uniaxial tensile tests at 10 s at room temperature. The Strain Hardening rate, the Strain Hardening exponent and the Hardening capacity were obtained from true plastic stress-Strain curves. There were almost no second phases in the as-extruded Mg-Zn magnesium alloys. Average grain sizes of the four as-extruded alloys were about 17.8 μm. With increasing Zn content from 1 to 4 wt%, the Strain Hardening rate increased from 2850 MPa to 6810 MPa at (σ-σ) = 60 MPa, the Strain Hardening exponent n increased from 0.160 to 0.203, and the Hardening capacity, Hc increased from 1.17 to 2.34. The difference in Strain Hardening response of these Mg-Zn alloys might be mainly caused by weaker basal texture and more solute atoms in the α-Mg matrix with higher Zn content.
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Effect of Sn content on Strain Hardening behavior of as-extruded Mg-Sn alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Chaoyue Zhao, Xianhua Chen, Di ZhaoAbstract:Abstract The effects of Sn content on Strain Hardening behavior of as-extruded Mg-xSn (x = 1.3, 2.4, 3.6 and 4.7 wt%) binary alloys were investigated by uniaxial tensile tests at room temperature. Strain Hardening rate, Strain Hardening exponent and Hardening capacity were obtained from the true plastic stress-Strain curves. After hot extrusion, the as-extruded Mg-Sn alloys are mainly composed of α-Mg matrix and second phase Mg2Sn, which only exists in Mg-3Sn and Mg-4Sn. Average grain size decreases from 15.6 μm to 3.6 µm with Sn content increases from 1.3 to 4.7 wt%. The experimental results show that Sn content decreases Strain Hardening ability of as-extruded Mg-Sn alloys, but gives rise to an obvious elevation in tensile strength, yield strength and elongation of them. With increasing Sn content, Strain Hardening rate decreases from 3527 MPa to 1211 MPa at (σ-σ0.2) = 50 MPa, Strain Hardening exponent decreases from 0.21 to 0.13 and Hardening capacity decreases from 1.66 to 0.63. The variation in Strain Hardening behavior of Mg-Sn alloys with Sn content is discussed in terms of the influences of grain size and distribution of grain orientation.
Stefanie Sandlöbes - One of the best experts on this subject based on the ideXlab platform.
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strengthening and Strain Hardening mechanisms in a precipitation hardened high mn lightweight steel
Acta Materialia, 2017Co-Authors: Emanuel David Welsch, Stefanie Sandlöbes, Dirk Ponge, Michael Herbig, Pyuckpa Choi, Seyed Masood Hafez Haghighat, Ivan Bleskov, Tilmann Hickel, Marta LipinskachwalekAbstract:Abstract We report on the strengthening and Strain Hardening mechanisms in an aged high-Mn lightweight steel (Fe-30.4Mn-8Al-1.2C, wt.%) studied by electron channeling contrast imaging (ECCI), transmission electron microscopy (TEM), atom probe tomography (APT) and correlative TEM/APT. Upon isothermal annealing at 600 °C, nano-sized κ-carbides form, as characterized by TEM and APT. The resultant alloy exhibits high strength and excellent ductility accompanied by a high constant Strain Hardening rate. In comparison to the as-quenched κ-free state, the precipitation of κ-carbides leads to a significant increase in yield strength (∼480 MPa) without sacrificing much tensile elongation. To study the strengthening and Strain Hardening behavior of the precipitation-hardened material, deformation microstructures were analyzed at different Strain levels. TEM and correlative TEM/APT results show that the κ-carbides are primarily sheared by lattice dislocations, gliding on the typical face-centered-cubic (fcc) slip system {111} , leading to particle dissolution and solute segregation. Ordering strengthening is the predominant strengthening mechanism. As the deformation substructure is characterized by planar slip bands, we quantitatively studied the evolution of the slip band spacing during Straining to understand the Strain Hardening behavior. A good agreement between the calculated flow stresses and the experimental data suggests that dynamic slip band refinement is the main Strain Hardening mechanism. The influence of κ-carbides on mechanical properties is discussed by comparing the results with that of the same alloy in the as-quenched, κ-free state.
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Strain Hardening by dynamic slip band refinement in a high mn lightweight steel
Acta Materialia, 2016Co-Authors: Emanuel David Welsch, Stefanie Sandlöbes, S Hafez M Haghighat, Stefan Zaefferer, Dirk Ponge, Michael Herbig, Pyuckpa Choi, Dierk RaabeAbstract:Abstract The Strain Hardening mechanism of a high-Mn lightweight steel (Fe-30.4Mn-8Al-1.2C (wt%)) is investigated by electron channeling contrast imaging (ECCI) and transmission electron microscopy (TEM). The alloy is characterized by a constant high Strain Hardening rate accompanied by high strength and high ductility (ultimate tensile strength: 900 MPa, elongation to fracture: 68%). Deformation microstructures at different Strain levels are studied in order to reveal and quantify the governing structural parameters at micro- and nanometer scales. As the material deforms mainly by planar dislocation slip causing the formation of slip bands, we quantitatively study the evolution of the slip band spacing during Straining. The flow stress is calculated from the slip band spacing on the basis of the passing stress. The good agreement between the calculated values and the tensile test data shows dynamic slip band refinement as the main Strain Hardening mechanism, enabling the excellent mechanical properties. This novel Strain Hardening mechanism is based on the passing stress acting between co-planar slip bands in contrast to earlier attempts to explain the Strain Hardening in high-Mn lightweight steels that are based on grain subdivision by microbands. We discuss in detail the formation of the finely distributed slip bands and the gradual reduction of the spacing between them, leading to constantly high Strain Hardening. TEM investigations of the precipitation state in the as-quenched state show finely dispersed atomically ordered clusters (size
Andrej Atrens - One of the best experts on this subject based on the ideXlab platform.
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Strain Hardening of as extruded mg xzn x 1 2 3 and 4 wt alloys
Journal of Materials Science & Technology, 2019Co-Authors: Chaoyue Zhao, Teng Tu, Xianhua Chen, Jingfeng Wang, Andrej AtrensAbstract:The influence of Zn on the Strain Hardening of as-extruded Mg-xZn (x = 1, 2, 3 and 4 wt%) magnesium alloys was investigated using uniaxial tensile tests at 10 s at room temperature. The Strain Hardening rate, the Strain Hardening exponent and the Hardening capacity were obtained from true plastic stress-Strain curves. There were almost no second phases in the as-extruded Mg-Zn magnesium alloys. Average grain sizes of the four as-extruded alloys were about 17.8 μm. With increasing Zn content from 1 to 4 wt%, the Strain Hardening rate increased from 2850 MPa to 6810 MPa at (σ-σ) = 60 MPa, the Strain Hardening exponent n increased from 0.160 to 0.203, and the Hardening capacity, Hc increased from 1.17 to 2.34. The difference in Strain Hardening response of these Mg-Zn alloys might be mainly caused by weaker basal texture and more solute atoms in the α-Mg matrix with higher Zn content.
