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Marko Knezevic - One of the best experts on this subject based on the ideXlab platform.
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mechanical behavior and texture evolution of we43 magnesium Rare Earth Alloy in split hopkinson pressure bar and taylor impact cylinder testing
International Journal of Impact Engineering, 2020Co-Authors: Daniel J Savage, Brandon Mcwilliams, Sven C Vogel, Carl P Trujillo, Irene J Beyerlein, Marko KnezevicAbstract:Abstract Mechanical behavior and texture evolution of Mg Rare-Earth Alloy WE43 is investigated for strain-rates 10−3/s to upwards of 105/s for the two material conditions - as-cast (AC) and T6 age hardened, rolled plate (RT6). The high strain-rate behavior is tested using both Taylor cylinder impact tests (TC) and split Hopkinson pressure bar tests (SHB) and bulk textures are obtained using neutron diffraction. Unlike the quasi-static strained material, AC and RT6 SHB retained high hardening rates throughout the test, even up to 30% true strain. Moreover, the high strain-rate data revealed that the RT6 material has a much higher strength than the AC material, but similar hardening rates despite significantly different initial texture. The flow stress near yield increased up to 10% for RT6 and up to 30% for AC as the strain-rate increased six orders of magnitude from quasi-static rates 10−3/s to 103/s. Neither material exhibited significant plastic anisotropy over the broad range of strain rates, despite the fact that the RT6 material had a moderately strong initial texture. In the TC tests, the geometric cross-sectional changes and texture along the cylinder from the cylindrical sample foot to head are measured and from the neutron diffraction texture analysis, upper-bound estimates of twin volume fraction are obtained as well as dislocation density from analyzing diffraction peak broadening. Recorded geometrical changes along several loading directions show that the material has deformed homogeneously under impact. Analysis of deformed textures indicates that { 10 1 ¯ 2 } extension deformation twinning occurred in the RT6 condition over the range of strain rates, with an upper bound estimate of 40% twin volume fraction for approximately 0.10-0.25 true strain. The peak texture components after the impact have their c-axes closely aligned with the impact direction. These observations are presented and rationalized in the paper.
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mechanical response twinning and texture evolution of we43 magnesium Rare Earth Alloy as a function of strain rate experiments and multi level crystal plasticity modeling
International Journal of Plasticity, 2019Co-Authors: William G Feather, Mohammad Jahedi, Brandon Mcwilliams, Chongchen Xiang, Nikhil Gupta, Daniel J Savage, Sven C Vogel, Saeede Ghorbanpour, Milan Ardeljan, Marko KnezevicAbstract:Abstract This work adapts a recently developed multi-level constitutive model for polycrystalline metals that deform by a combination of elasticity, crystallographic slip, and deformation twinning to interpret the deformation behavior of Alloy WE43 as a function of strain rate. The model involves a two-level homogenization scheme. First, to relate the grain level to the level of a polycrystalline aggregate, a Taylor-type model is used. Second, to relate the aggregate level response at each finite element (FE) integration point to the macro-level, an implicit FE approach is employed. The model features a dislocation-based hardening law governing the activation stress at the slip and twin system level, taking into account the effects of temperature and strain rate through thermally-activated recovery, dislocation debris formation, and slip-twin interactions. The twinning model employs a composite grain approach for multiple twin variants and considers double twinning. The Alloy is tested in simple compression and tension at a quasi-static deformation rate and in compression under high strain rates at room temperature. Microstructure evolution of the Alloy is characterized using electron backscattered diffraction and neutron diffraction. Taking the measured initial texture as inputs, it is shown that the model successfully captures mechanical responses, twinning, and texture evolution using a single set of hardening parameters, which are associated with the thermally activated rate law for dislocation density across strain rates. The model internally adjusts relative amounts of active deformation modes based on evolution of slip and twin resistances during the imposed loadings to predict the deformation characteristics. We observe that WE43 exhibits much higher strain-hardening rates under high strain rate deformation than under quasi-static deformation. The observation is rationalized as primarily originating from the pronounced activation of twins and especially contraction and double twins during high strain rate deformation. These twins are effective in strain hardening of the Alloy through the texture and barrier hardening effects.
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Deformation and fracture mechanisms in WE43 magnesium-Rare Earth Alloy fabricated by direct-chill casting and rolling
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Mohammad Jahedi, Brandon Mcwilliams, Marko KnezevicAbstract:Abstract This paper examines deformation behavior of WE43 Alloy in direct-chill as-cast (as-cast-WE43) and rolled heat-treated T6 (WE43-T6) conditions with an emphasis on fracture mechanisms. Unlike many Mg allows, as-cast-WE43 and WE43-T6 exhibit no tension/compression asymmetry in their yield stress. WE43-T6 material shows more anisotropy in yield stress than as-cast-WE43, which is attributed to their respected initial crystallographic textures. Both WE43-T6 and as-cast-WE43 exhibit some anisotropy in strain hardening due to texture evolution and deformation twinning. Both materials show a small elongation to fracture of approximately 6% in tension. In contrast, strain to fracture in compression is large. Crystallographic texture evolves substantially in compression, where crystals are slowly reorienting their crystallographic c -axis parallel to the loading direction with plastic strain. Both materials fracture by a typical shear fracture in compression. Fractographic analysis of fractured surfaces in compression for WE43-T6 reveals evidence of transgranular facets that are much larger than grain size with minor content of microvoid coalescence. Although elongation to fracture in tension is small with no necking, detailed analysis of fracture surfaces reveals evidence of ductile microvoid coalescence. However, the intergranular fracture character, especially in the central high stress triaxiality region of the samples, limits the ductility of the material.
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rate and temperature dependent deformation behavior of as cast we43 magnesium Rare Earth Alloy manufactured by direct chill casting
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Mohammad Jahedi, Brandon Mcwilliams, Irene J Beyerlein, Franklin R Kellogg, Marko KnezevicAbstract:Abstract In this work, we study the deformation behavior of a direct chill cast WE43 Mg Alloy. This material initially has equiaxed grains approximately 40 µm in diameter and a random texture. The room temperature, quasi-static response exhibits little plastic anisotropy when evaluated parallel to and normal to the solidification direction and no initial yield tension-compression asymmetry. The deformation at room temperature is accompanied by significant basal texture development and formation of three types of deformation twins: { 10 1 2 } 〈 1 011 〉 , { 10 1 1 } 〈 10 12 〉 , and { 11 2 1 } 〈 1 1 26 〉 as well as double twins { 10 1 1 } 〈 10 12 〉 - { 10 1 2 } 〈 1 011 〉 , although each in small amounts 1.0 true strain) without fracturing.
Jie Dong - One of the best experts on this subject based on the ideXlab platform.
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Effects of Heat Input on Microstructure and Mechanical Properties of Laser-Welded Mg-Rare Earth Alloy
Journal of Materials Engineering and Performance, 2012Co-Authors: Jun Dai, Jian Huang, Jie DongAbstract:The effects of heat input on the quality of laser-welded Mg-Rare Earth Alloy NZ30K were studied. Using a 15-kW high-power CO2 laser, the microstructure and mechanical properties of welded joints under different heat inputs had been analyzed and tested. It is found that the welding heat input plays an important role in laser welding of NZ30K. Good welded joint without macroscopic defects can be obtained using the proper heat input. With the increasing heat input, welding penetration gets deeper, the width of the heat-affected-zone becomes larger, and the distribution of precipitates changes concentration. Tensile tests display that the ultimate tensile strength (UTS) of the welded joint tends to increase at first with the increasing heat input. After the welded joint gets full penetration, the UTS remains almost the same, although the heat input is increased.
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Effects of heat treatments on laser welded Mg-Rare Earth Alloy NZ30K
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011Co-Authors: Jun Dai, Li Min, Jian Huang, Jie DongAbstract:Abstract In this study, the effects of heat treatments on the quality of laser welded Mg-Rare Earth Alloy NZ30K were systematically studied. The microstructure and mechanical properties of joints, welded by a 15 kW high power CO 2 laser, under different heat treatments had been tested and analyzed. The results indicated that the heat treatment plays an important role in the mechanical strength of laser welded joint of NZ30K. The microstructure of samples after the solution treatment as well as aging treatment is different from that of the as-received welded joint. For solution treatment, although the microstructure is much different from that of as-received welded joint, the solution strengthening effect is not obvious. There are lots of precipitates in the fusion zone after the aging treatment, which will significantly enhance the ultimate tensile strength (UTS) and the yield tensile strength (YTS) of the welding joint. 79% of YTS is caused by precipitation strengthening. Therefore, the results implied that the UTS and YTS can be greatly improved by proper heat treatment.
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Laser Hybrid Welding Processing of Mg-Rare Earth Alloy
Advanced Materials Research, 2011Co-Authors: Jun Dai, Jian Huang, Jie DongAbstract:The welding processing of Mg-Rare Earth Alloy NZ30K was studied using laser-TIG hybrid welding. For comparison the NZ30K Alloy was also welded by the gas tungsten arc (TIG) and laser beam respectively. The microstructure of the welded joints had been analyzed. The hybrid welding method could refine the grains in the fusion and improve the tensile strength of the welded joints obviously. The arc plasma and the laser-induced plasma during welding were recorded by a high speed camera and the area of the plasma was calculated through image processing technology. Among the three welding processes the plasma area of the hybrid welding is the largest, but not a simple addition of the TIG welding and laser welding. The results show that Mg-Rare Earth Alloy NZ30K can be well joined using the laser-TIG hybrid welding method.
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forgeability and die forging forming of direct chill casting mg nd zn zr magnesium Alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010Co-Authors: Xingwei Zheng, Jie Dong, D D Yin, Wencai Liu, Fenghua Wang, Li Jin, Wenjiang DingAbstract:Abstract Mg–3.0Nd–0.2Zn–0.4Zr (wt.%, NZ30K) is a newly developed magnesium Rare Earth Alloy with middle strength and high toughness in as-cast state. In this paper the forgeability of the as-cast NZ30K Alloy prepared by direct chill (DC) casting was studied. The forgeability of the DC casting NZ30K Alloy was firstly modeled by using uniaxial tensile and compression tests at temperatures between 250 and 400 °C and strain rates ranging from 0.001 to 10 S−1. The results show that the optimum forging temperature of the as-cast NZ30K Alloy is between 350 and 400 °C and strain rate ranges from 0.01 to 1 S−1. Finally, a flange of automobile clutch was tentatively and successfully forged by using the DC casting NZ30K billet. The forged flange possesses desired microstructure and high mechanical properties. The mechanical properties of the product are further enhanced by T5 heat treatment for precipitate strengthening. The maximum ultimate tensile strength, yield strength and elongation of the T5 state Alloy are 323.5 MPa, 318.2 MPa and 11.2%, respectively. The creep strain rates for the NZ30K Alloy are 2.0 × 10−8 and 1.2 × 10−7 at the 200 and 250 °C, respectively.
Jun Dai - One of the best experts on this subject based on the ideXlab platform.
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Effects of Aging Treatment on Laser-Welded Mg-Rare Earth Alloy NZ30K
Advances in Materials Science and Engineering, 2013Co-Authors: Jun Dai, Li Yang, Guo Guolin, Guo LanzhongAbstract:Magnesium-Rare Earth Alloys have received extensive attention due to their attractive mechanical properties resulting from high density of precipitation. The precipitation sequence in laser-welded Mg-3Nd-0.2Zn-0.4Zr (NZ30K) Alloy during aging treatment at 200°C and 225°C has been investigated using transmission electron microscopy (TEM). The results indicate that the tensile strength of laser-welded NZ30K can be improved significantly after aging treatment at 200°C for 8 h. It is found that the precipitation in laser-welded NZ30K Alloy follows the sequence of supersaturated solid solution → β′′(DO19) → β′(fcc).
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Effects of Heat Input on Microstructure and Mechanical Properties of Laser-Welded Mg-Rare Earth Alloy
Journal of Materials Engineering and Performance, 2012Co-Authors: Jun Dai, Jian Huang, Jie DongAbstract:The effects of heat input on the quality of laser-welded Mg-Rare Earth Alloy NZ30K were studied. Using a 15-kW high-power CO2 laser, the microstructure and mechanical properties of welded joints under different heat inputs had been analyzed and tested. It is found that the welding heat input plays an important role in laser welding of NZ30K. Good welded joint without macroscopic defects can be obtained using the proper heat input. With the increasing heat input, welding penetration gets deeper, the width of the heat-affected-zone becomes larger, and the distribution of precipitates changes concentration. Tensile tests display that the ultimate tensile strength (UTS) of the welded joint tends to increase at first with the increasing heat input. After the welded joint gets full penetration, the UTS remains almost the same, although the heat input is increased.
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Effects of heat treatments on laser welded Mg-Rare Earth Alloy NZ30K
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011Co-Authors: Jun Dai, Li Min, Jian Huang, Jie DongAbstract:Abstract In this study, the effects of heat treatments on the quality of laser welded Mg-Rare Earth Alloy NZ30K were systematically studied. The microstructure and mechanical properties of joints, welded by a 15 kW high power CO 2 laser, under different heat treatments had been tested and analyzed. The results indicated that the heat treatment plays an important role in the mechanical strength of laser welded joint of NZ30K. The microstructure of samples after the solution treatment as well as aging treatment is different from that of the as-received welded joint. For solution treatment, although the microstructure is much different from that of as-received welded joint, the solution strengthening effect is not obvious. There are lots of precipitates in the fusion zone after the aging treatment, which will significantly enhance the ultimate tensile strength (UTS) and the yield tensile strength (YTS) of the welding joint. 79% of YTS is caused by precipitation strengthening. Therefore, the results implied that the UTS and YTS can be greatly improved by proper heat treatment.
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Research on Laser Welding of Mg-Rare Earth Alloy Mg-3Nd-0.2Zn-0.4Zr
Journal of Materials Engineering and Performance, 2011Co-Authors: Jun Dai, Jian HuangAbstract:The welding process of Mg-Rare Earth Alloy Mg-3Nd-0.2Zn-0.4Zr (NZ30K) was studied using 15 kW high-power CO2 laser, the microstructure and performance of the typical welded joints had been analyzed and tested. There is no softening zone according to the microhardness test of the welded joint. The microstructure of the fusion zone consists of α-Mg-phase and β-phase (Mg12Nd).The results show that Mg-Rare Earth Alloy NZ30K can be well joined with the high power laser and the welded joint has good performance.
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Laser Hybrid Welding Processing of Mg-Rare Earth Alloy
Advanced Materials Research, 2011Co-Authors: Jun Dai, Jian Huang, Jie DongAbstract:The welding processing of Mg-Rare Earth Alloy NZ30K was studied using laser-TIG hybrid welding. For comparison the NZ30K Alloy was also welded by the gas tungsten arc (TIG) and laser beam respectively. The microstructure of the welded joints had been analyzed. The hybrid welding method could refine the grains in the fusion and improve the tensile strength of the welded joints obviously. The arc plasma and the laser-induced plasma during welding were recorded by a high speed camera and the area of the plasma was calculated through image processing technology. Among the three welding processes the plasma area of the hybrid welding is the largest, but not a simple addition of the TIG welding and laser welding. The results show that Mg-Rare Earth Alloy NZ30K can be well joined using the laser-TIG hybrid welding method.
Jian Huang - One of the best experts on this subject based on the ideXlab platform.
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Effects of Heat Input on Microstructure and Mechanical Properties of Laser-Welded Mg-Rare Earth Alloy
Journal of Materials Engineering and Performance, 2012Co-Authors: Jun Dai, Jian Huang, Jie DongAbstract:The effects of heat input on the quality of laser-welded Mg-Rare Earth Alloy NZ30K were studied. Using a 15-kW high-power CO2 laser, the microstructure and mechanical properties of welded joints under different heat inputs had been analyzed and tested. It is found that the welding heat input plays an important role in laser welding of NZ30K. Good welded joint without macroscopic defects can be obtained using the proper heat input. With the increasing heat input, welding penetration gets deeper, the width of the heat-affected-zone becomes larger, and the distribution of precipitates changes concentration. Tensile tests display that the ultimate tensile strength (UTS) of the welded joint tends to increase at first with the increasing heat input. After the welded joint gets full penetration, the UTS remains almost the same, although the heat input is increased.
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Effects of heat treatments on laser welded Mg-Rare Earth Alloy NZ30K
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011Co-Authors: Jun Dai, Li Min, Jian Huang, Jie DongAbstract:Abstract In this study, the effects of heat treatments on the quality of laser welded Mg-Rare Earth Alloy NZ30K were systematically studied. The microstructure and mechanical properties of joints, welded by a 15 kW high power CO 2 laser, under different heat treatments had been tested and analyzed. The results indicated that the heat treatment plays an important role in the mechanical strength of laser welded joint of NZ30K. The microstructure of samples after the solution treatment as well as aging treatment is different from that of the as-received welded joint. For solution treatment, although the microstructure is much different from that of as-received welded joint, the solution strengthening effect is not obvious. There are lots of precipitates in the fusion zone after the aging treatment, which will significantly enhance the ultimate tensile strength (UTS) and the yield tensile strength (YTS) of the welding joint. 79% of YTS is caused by precipitation strengthening. Therefore, the results implied that the UTS and YTS can be greatly improved by proper heat treatment.
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Research on Laser Welding of Mg-Rare Earth Alloy Mg-3Nd-0.2Zn-0.4Zr
Journal of Materials Engineering and Performance, 2011Co-Authors: Jun Dai, Jian HuangAbstract:The welding process of Mg-Rare Earth Alloy Mg-3Nd-0.2Zn-0.4Zr (NZ30K) was studied using 15 kW high-power CO2 laser, the microstructure and performance of the typical welded joints had been analyzed and tested. There is no softening zone according to the microhardness test of the welded joint. The microstructure of the fusion zone consists of α-Mg-phase and β-phase (Mg12Nd).The results show that Mg-Rare Earth Alloy NZ30K can be well joined with the high power laser and the welded joint has good performance.
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Laser Hybrid Welding Processing of Mg-Rare Earth Alloy
Advanced Materials Research, 2011Co-Authors: Jun Dai, Jian Huang, Jie DongAbstract:The welding processing of Mg-Rare Earth Alloy NZ30K was studied using laser-TIG hybrid welding. For comparison the NZ30K Alloy was also welded by the gas tungsten arc (TIG) and laser beam respectively. The microstructure of the welded joints had been analyzed. The hybrid welding method could refine the grains in the fusion and improve the tensile strength of the welded joints obviously. The arc plasma and the laser-induced plasma during welding were recorded by a high speed camera and the area of the plasma was calculated through image processing technology. Among the three welding processes the plasma area of the hybrid welding is the largest, but not a simple addition of the TIG welding and laser welding. The results show that Mg-Rare Earth Alloy NZ30K can be well joined using the laser-TIG hybrid welding method.
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Microstructure and Mechanical Properties of High Power CO2 Laser Welded Joint of Mg-Rare Earth Alloy NZ30K
Physics Procedia, 2010Co-Authors: Jun Dai, Jian HuangAbstract:The weldability of a 9.5 mm thick Mg-Rare Earth Alloy NZ30K using 15 kW high power CO2 laser was studied. The microstructure and mechanical properties of the typical welded joints had been analyzed and tested. When using the right laser welding parameters, good weld forming can be obtained. The microstructure of the fusion zone is small equiaxed grains. There is no softening zone to be observed according to the micro-hardness distribution across the welded joints. The results show that the thick Mg-Rare Earth Alloy NZ30K plate can be welded by the high power CO2 laser with good weld quality.
Brandon Mcwilliams - One of the best experts on this subject based on the ideXlab platform.
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mechanical behavior and texture evolution of we43 magnesium Rare Earth Alloy in split hopkinson pressure bar and taylor impact cylinder testing
International Journal of Impact Engineering, 2020Co-Authors: Daniel J Savage, Brandon Mcwilliams, Sven C Vogel, Carl P Trujillo, Irene J Beyerlein, Marko KnezevicAbstract:Abstract Mechanical behavior and texture evolution of Mg Rare-Earth Alloy WE43 is investigated for strain-rates 10−3/s to upwards of 105/s for the two material conditions - as-cast (AC) and T6 age hardened, rolled plate (RT6). The high strain-rate behavior is tested using both Taylor cylinder impact tests (TC) and split Hopkinson pressure bar tests (SHB) and bulk textures are obtained using neutron diffraction. Unlike the quasi-static strained material, AC and RT6 SHB retained high hardening rates throughout the test, even up to 30% true strain. Moreover, the high strain-rate data revealed that the RT6 material has a much higher strength than the AC material, but similar hardening rates despite significantly different initial texture. The flow stress near yield increased up to 10% for RT6 and up to 30% for AC as the strain-rate increased six orders of magnitude from quasi-static rates 10−3/s to 103/s. Neither material exhibited significant plastic anisotropy over the broad range of strain rates, despite the fact that the RT6 material had a moderately strong initial texture. In the TC tests, the geometric cross-sectional changes and texture along the cylinder from the cylindrical sample foot to head are measured and from the neutron diffraction texture analysis, upper-bound estimates of twin volume fraction are obtained as well as dislocation density from analyzing diffraction peak broadening. Recorded geometrical changes along several loading directions show that the material has deformed homogeneously under impact. Analysis of deformed textures indicates that { 10 1 ¯ 2 } extension deformation twinning occurred in the RT6 condition over the range of strain rates, with an upper bound estimate of 40% twin volume fraction for approximately 0.10-0.25 true strain. The peak texture components after the impact have their c-axes closely aligned with the impact direction. These observations are presented and rationalized in the paper.
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mechanical response twinning and texture evolution of we43 magnesium Rare Earth Alloy as a function of strain rate experiments and multi level crystal plasticity modeling
International Journal of Plasticity, 2019Co-Authors: William G Feather, Mohammad Jahedi, Brandon Mcwilliams, Chongchen Xiang, Nikhil Gupta, Daniel J Savage, Sven C Vogel, Saeede Ghorbanpour, Milan Ardeljan, Marko KnezevicAbstract:Abstract This work adapts a recently developed multi-level constitutive model for polycrystalline metals that deform by a combination of elasticity, crystallographic slip, and deformation twinning to interpret the deformation behavior of Alloy WE43 as a function of strain rate. The model involves a two-level homogenization scheme. First, to relate the grain level to the level of a polycrystalline aggregate, a Taylor-type model is used. Second, to relate the aggregate level response at each finite element (FE) integration point to the macro-level, an implicit FE approach is employed. The model features a dislocation-based hardening law governing the activation stress at the slip and twin system level, taking into account the effects of temperature and strain rate through thermally-activated recovery, dislocation debris formation, and slip-twin interactions. The twinning model employs a composite grain approach for multiple twin variants and considers double twinning. The Alloy is tested in simple compression and tension at a quasi-static deformation rate and in compression under high strain rates at room temperature. Microstructure evolution of the Alloy is characterized using electron backscattered diffraction and neutron diffraction. Taking the measured initial texture as inputs, it is shown that the model successfully captures mechanical responses, twinning, and texture evolution using a single set of hardening parameters, which are associated with the thermally activated rate law for dislocation density across strain rates. The model internally adjusts relative amounts of active deformation modes based on evolution of slip and twin resistances during the imposed loadings to predict the deformation characteristics. We observe that WE43 exhibits much higher strain-hardening rates under high strain rate deformation than under quasi-static deformation. The observation is rationalized as primarily originating from the pronounced activation of twins and especially contraction and double twins during high strain rate deformation. These twins are effective in strain hardening of the Alloy through the texture and barrier hardening effects.
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Deformation and fracture mechanisms in WE43 magnesium-Rare Earth Alloy fabricated by direct-chill casting and rolling
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Mohammad Jahedi, Brandon Mcwilliams, Marko KnezevicAbstract:Abstract This paper examines deformation behavior of WE43 Alloy in direct-chill as-cast (as-cast-WE43) and rolled heat-treated T6 (WE43-T6) conditions with an emphasis on fracture mechanisms. Unlike many Mg allows, as-cast-WE43 and WE43-T6 exhibit no tension/compression asymmetry in their yield stress. WE43-T6 material shows more anisotropy in yield stress than as-cast-WE43, which is attributed to their respected initial crystallographic textures. Both WE43-T6 and as-cast-WE43 exhibit some anisotropy in strain hardening due to texture evolution and deformation twinning. Both materials show a small elongation to fracture of approximately 6% in tension. In contrast, strain to fracture in compression is large. Crystallographic texture evolves substantially in compression, where crystals are slowly reorienting their crystallographic c -axis parallel to the loading direction with plastic strain. Both materials fracture by a typical shear fracture in compression. Fractographic analysis of fractured surfaces in compression for WE43-T6 reveals evidence of transgranular facets that are much larger than grain size with minor content of microvoid coalescence. Although elongation to fracture in tension is small with no necking, detailed analysis of fracture surfaces reveals evidence of ductile microvoid coalescence. However, the intergranular fracture character, especially in the central high stress triaxiality region of the samples, limits the ductility of the material.
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rate and temperature dependent deformation behavior of as cast we43 magnesium Rare Earth Alloy manufactured by direct chill casting
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Mohammad Jahedi, Brandon Mcwilliams, Irene J Beyerlein, Franklin R Kellogg, Marko KnezevicAbstract:Abstract In this work, we study the deformation behavior of a direct chill cast WE43 Mg Alloy. This material initially has equiaxed grains approximately 40 µm in diameter and a random texture. The room temperature, quasi-static response exhibits little plastic anisotropy when evaluated parallel to and normal to the solidification direction and no initial yield tension-compression asymmetry. The deformation at room temperature is accompanied by significant basal texture development and formation of three types of deformation twins: { 10 1 2 } 〈 1 011 〉 , { 10 1 1 } 〈 10 12 〉 , and { 11 2 1 } 〈 1 1 26 〉 as well as double twins { 10 1 1 } 〈 10 12 〉 - { 10 1 2 } 〈 1 011 〉 , although each in small amounts 1.0 true strain) without fracturing.
