Pub Date : 2025-01-09DOI: 10.1016/j.jma.2024.12.011
Lang Liu, Xuan Luo, Konstantinos Papadikis, Yunchang Xin, Qing Liu
Atomistic simulations were adopted to study the solute segregation effect on dislocation transmutation across the <span><span style=""></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><mo is="true">{</mo><mrow is="true"><mn is="true">10</mn><mover accent="true" is="true"><mn is="true">1</mn><mo is="true">¯</mo></mover><mn is="true">2</mn></mrow><mo is="true">}</mo></mrow></math>' role="presentation" style="font-size: 90%; display: inline-block; position: relative;" tabindex="0"><svg aria-hidden="true" focusable="false" height="2.779ex" role="img" style="vertical-align: -0.812ex;" viewbox="0 -846.5 3073 1196.3" width="7.137ex" xmlns:xlink="http://www.w3.org/1999/xlink"><g fill="currentColor" stroke="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><use is="true" xlink:href="#MJMAIN-7B"></use><g is="true" transform="translate(500,0)"><g is="true"><use xlink:href="#MJMAIN-31"></use><use x="500" xlink:href="#MJMAIN-30" y="0"></use></g><g is="true" transform="translate(1001,0)"><g is="true" transform="translate(35,0)"><use xlink:href="#MJMAIN-31"></use></g><g is="true" transform="translate(0,198)"><use x="-70" xlink:href="#MJMAIN-AF" y="0"></use><use x="70" xlink:href="#MJMAIN-AF" y="0"></use></g></g><g is="true" transform="translate(1571,0)"><use xlink:href="#MJMAIN-32"></use></g></g><use is="true" x="2572" xlink:href="#MJMAIN-7D" y="0"></use></g></g></svg><span role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><mrow is="true"><mo is="true">{</mo><mrow is="true"><mn is="true">10</mn><mover accent="true" is="true"><mn is="true">1</mn><mo is="true">¯</mo></mover><mn is="true">2</mn></mrow><mo is="true">}</mo></mrow></math></span></span><script type="math/mml"><math><mrow is="true"><mo is="true">{</mo><mrow is="true"><mn is="true">10</mn><mover accent="true" is="true"><mn is="true">1</mn><mo is="true">¯</mo></mover><mn is="true">2</mn></mrow><mo is="true">}</mo></mrow></math></script></span> twin boundaries in magnesium. For pure magnesium, the dislocation-twin reaction resulted in the formation of sessile dislocations accompanied by the fast migration of the twin boundary, and no 〈<em>c</em> + <em>a</em>〉 dislocation occurred. With Al segregation, instead, two basal dislocations transmuted into one prismatic 〈<em>c</em> + <em>a</em>〉 dislocation in the twin. Twin migration was significantly impeded, and the resultant twin disconnections stayed localized and had a higher step character than in pure Mg. To reveal the mechanism of the effect of solute segregation, the Peierls barriers of twin disconnections were calculated, and the dynamic evolutions of twin disconnection dipoles were simulated. The results suggested that Al segregation softened the Peierls barrier of twin disconnections but imposed a high pinning force on twin disconnection
采用原子模拟方法研究了溶质偏析对镁中{101¯2}{101¯2}孪晶界位错嬗变的影响。对于纯镁，位错-孪晶反应导致固位错形成，孪晶界快速迁移，没有出现< c + a >位错。在Al偏析中，两个基底位错转变为一个棱柱形< c +一个>位错。与纯Mg相比，孪晶迁移受到明显阻碍，导致孪晶断裂停留在局部，且具有更高的阶跃特征。为了揭示溶质偏析的作用机理，计算了孪晶断裂的Peierls势垒，并模拟了孪晶断裂偶极子的动态演化。结果表明，Al偏析软化了孪晶断口的Peierls势垒，但对孪晶断口施加了较大的钉住力，从而减弱了它们的迁移率。此外，在相同的Al偏析条件下，高阶的孪晶断开偶极子表现出更大的稳定性，这解释了在Al偏析的情况下，比纯镁中存在高阶的局部孪晶断开。溶质偏析导致孪晶断开的低迁移率导致< c + a >位错的发生。
{"title":"Effect of Al segregation on dislocation transmutation across {101¯2} twin boundaries in Mg: An atomistic simulation study","authors":"Lang Liu, Xuan Luo, Konstantinos Papadikis, Yunchang Xin, Qing Liu","doi":"10.1016/j.jma.2024.12.011","DOIUrl":"https://doi.org/10.1016/j.jma.2024.12.011","url":null,"abstract":"Atomistic simulations were adopted to study the solute segregation effect on dislocation transmutation across the <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 3073 1196.3\" width=\"7.137ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use is=\"true\" xlink:href=\"#MJMAIN-7B\"></use><g is=\"true\" transform=\"translate(500,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-32\"></use></g></g><use is=\"true\" x=\"2572\" xlink:href=\"#MJMAIN-7D\" y=\"0\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow></math></script></span> twin boundaries in magnesium. For pure magnesium, the dislocation-twin reaction resulted in the formation of sessile dislocations accompanied by the fast migration of the twin boundary, and no 〈<em>c</em> + <em>a</em>〉 dislocation occurred. With Al segregation, instead, two basal dislocations transmuted into one prismatic 〈<em>c</em> + <em>a</em>〉 dislocation in the twin. Twin migration was significantly impeded, and the resultant twin disconnections stayed localized and had a higher step character than in pure Mg. To reveal the mechanism of the effect of solute segregation, the Peierls barriers of twin disconnections were calculated, and the dynamic evolutions of twin disconnection dipoles were simulated. The results suggested that Al segregation softened the Peierls barrier of twin disconnections but imposed a high pinning force on twin disconnection","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"31 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The primary magnesium production is accompanied by a large amount of magnesium slag (MS) discharge. The low hydration reactivity of γ-Ca2SiO4 (γ-C2S) and MgO in MS results in the volume stability issue and low utilization rate of MS. To eliminate the issue, this study proposes to pre-autoclave the MS slurry to boost the hydration of γ-C2S and MgO and then utilize their hydration products to prepare cementitious materials by carbonation curing. MgO from MS and prepared γ-C2S are firstly employed as study objects respectively, for they are the main contents of magnesium slag. The results indicate that pre-autoclaving treatment can strongly elevate the hydration degree of MgO from MS, this can substantially solve the volume stability issue of MS. Meanwhile, the pre-autoclaving of γ-C2S induces the generation of crystallized and amorphous C-S-H products, and both products could promote the carbonation reaction when compared to γ-C2S. The carbonation degree of pre-autoclaved MS firstly increases and then decreases with the rising pre-autoclaving temperature, and the optimal pre-autoclaving temperature for MS carbonation is 160 °C, at this time, the powdered MS can be simply carbonated fully. The sample made of pre-autoclaved MS and then subjected to 4 h carbonation could achieve the compressive strength of 29 MPa. with good soundness. During volume stability testing, the volume expansion rate of a carbonated MS sample with pre-autoclaving was 0.07 %, which is significantly lower than the normal requirement of 0.5 %. This research offers a novel approach to utilizing magnesium slag in building materials and contributes to carbon reduction.
{"title":"Effect of pre-autoclaving treatment on volume stability and compressive strength of carbonated magnesium slag","authors":"Xin Xu, Jinhui Liu, Yuandong Mu, Yixin Zhang, Yuming Zhao, Peixu Yang, Weidong Zhang, Xiaofeng Li, Yong Hu, Weineng Tang, Jiajia Tian, Zhongtao Luo, Shaojun Zhang","doi":"10.1016/j.jma.2024.12.016","DOIUrl":"https://doi.org/10.1016/j.jma.2024.12.016","url":null,"abstract":"The primary magnesium production is accompanied by a large amount of magnesium slag (MS) discharge. The low hydration reactivity of γ-Ca<sub>2</sub>SiO<sub>4</sub> (γ-C<sub>2</sub>S) and MgO in MS results in the volume stability issue and low utilization rate of MS. To eliminate the issue, this study proposes to pre-autoclave the MS slurry to boost the hydration of γ-C<sub>2</sub>S and MgO and then utilize their hydration products to prepare cementitious materials by carbonation curing. MgO from MS and prepared γ-C<sub>2</sub>S are firstly employed as study objects respectively, for they are the main contents of magnesium slag. The results indicate that pre-autoclaving treatment can strongly elevate the hydration degree of MgO from MS, this can substantially solve the volume stability issue of MS. Meanwhile, the pre-autoclaving of γ-C<sub>2</sub>S induces the generation of crystallized and amorphous C-S-H products, and both products could promote the carbonation reaction when compared to γ-C<sub>2</sub>S. The carbonation degree of pre-autoclaved MS firstly increases and then decreases with the rising pre-autoclaving temperature, and the optimal pre-autoclaving temperature for MS carbonation is 160 °C, at this time, the powdered MS can be simply carbonated fully. The sample made of pre-autoclaved MS and then subjected to 4 h carbonation could achieve the compressive strength of 29 MPa. with good soundness. During volume stability testing, the volume expansion rate of a carbonated MS sample with pre-autoclaving was 0.07 %, which is significantly lower than the normal requirement of 0.5 %. This research offers a novel approach to utilizing magnesium slag in building materials and contributes to carbon reduction.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"1 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142925084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing efficient catalysts is pivotal for advancing MgH2-based hydrogen storage systems. In this study, a novel catalyst, graphene oxide-supported oxygen vacancy-rich Co3O4 and Ni nanoparticles (Ni-OV-C@GO), was synthesized to enhance the hydrogen storage performance of MgH2. The catalyst dramatically improved the kinetics of MgH2, lowering the initial hydrogen desorption temperature of Ni-OV-C@GO-MgH2–7 to 438 K, which is 386 K lower than that of as-milled MgH2. The composite achieved 5.0 wt% hydrogen absorption at 423 K within 600 s and retained 97.3 % capacity after 30 cycles. Notably, the activation energy for H2 desorption was reduced to 40.78 kJ/mol, an 80 % decrease compared to pristine MgH2. The in-situ formation of CoMg2/CoMg2H5 and Mg2Ni/Mg2NiH4 acted as “hydrogen pumps”, facilitating multiple hydrogen transfer pathways. Additionally, oxygen vacancies elongated Mg-H bonds, enhancing dehydrogenation kinetics through catalytic effects. These findings provide valuable insights into improving hydrogen adsorption and desorption kinetics in MgH2-based systems.
{"title":"Graphene oxide supported oxygen vacancy-rich Co3O4 and Ni nanoparticle for boosting the hydrogen storage properties of MgH2","authors":"Yazhou Wang, Yongpeng Xia, Enyong Xu, Cuili Xiang, Xue Qing, Zexuan Yang, Fen Xu, Lixian Sun, Yong Shen Chua, Yongjin Zou","doi":"10.1016/j.jma.2024.12.015","DOIUrl":"https://doi.org/10.1016/j.jma.2024.12.015","url":null,"abstract":"Developing efficient catalysts is pivotal for advancing MgH<sub>2</sub>-based hydrogen storage systems. In this study, a novel catalyst, graphene oxide-supported oxygen vacancy-rich Co<sub>3</sub>O<sub>4</sub> and Ni nanoparticles (Ni-O<sub>V</sub>-C@GO), was synthesized to enhance the hydrogen storage performance of MgH<sub>2</sub>. The catalyst dramatically improved the kinetics of MgH<sub>2</sub>, lowering the initial hydrogen desorption temperature of Ni-O<sub>V</sub>-C@GO-MgH<sub>2</sub>–7 to 438 K, which is 386 K lower than that of as-milled MgH<sub>2</sub>. The composite achieved 5.0 wt% hydrogen absorption at 423 K within 600 s and retained 97.3 % capacity after 30 cycles. Notably, the activation energy for H<sub>2</sub> desorption was reduced to 40.78 kJ/mol, an 80 % decrease compared to pristine MgH<sub>2</sub>. The <em>in-situ</em> formation of CoMg<sub>2</sub>/CoMg<sub>2</sub>H<sub>5</sub> and Mg<sub>2</sub>Ni/Mg<sub>2</sub>NiH<sub>4</sub> acted as “hydrogen pumps”, facilitating multiple hydrogen transfer pathways. Additionally, oxygen vacancies elongated Mg-H bonds, enhancing dehydrogenation kinetics through catalytic effects. These findings provide valuable insights into improving hydrogen adsorption and desorption kinetics in MgH<sub>2</sub>-based systems.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"14 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142917944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-03DOI: 10.1016/j.jma.2024.12.006
Rong Yu, Yang Tian, Bin Yang, Xiumin Chen, Baoqiang Xu, Wenlong Jiang, Tingzhuang Ma, Lipeng Wang, Dong Liang, Haosong Yu
A major problem facing the magnesium melting process is to address the oxidative combustion of magnesium. At present, there are still some problems in the method used to protect magnesium smelting. For example, the reaction of covering flux with magnesium melt is likely to produce a large number of toxic and harmful gasses (Cl2 and HCl), the cost of such reaction is high, and there is a lack of clarity on the protection mechanism of CO2 acting as the protective gas of magnesium melt. Therefore, a new process is proposed in this paper to isolate the air on the surface of magnesium melt using MgO-C-Mg film. Based on the thermodynamic theory of MgO-C-Mg film formation during crude magnesium smelting, an investigation is conducted into the effect of different experimental conditions on the protective effect of magnesium. Not only is the protective mechanism of MgO-C-Mg film revealed, it is also verified that the MgO-C-Mg film can produce a more pronounced protective effect at suitable temperature. According to thermodynamic analysis, magnesium melt reacts with CO2 to form magnesium oxide and C. CO2 consumes C when the experimental temperature exceeds 700 °C. This is contrary to the purpose of the experiment as it should be maintained at about 700 °C. The experimental results show that an obvious protective effect can be produced on the magnesium melt by the MgO-C-Mg film generated under the following conditions of 90% CO2–10% Ar, smelting temperature of 700 °C, holding time of 60 min, and stirring time of 20 min.
{"title":"Analysis of the protective behavior and mechanism of MgO-C-Mg film for crude magnesium smelting","authors":"Rong Yu, Yang Tian, Bin Yang, Xiumin Chen, Baoqiang Xu, Wenlong Jiang, Tingzhuang Ma, Lipeng Wang, Dong Liang, Haosong Yu","doi":"10.1016/j.jma.2024.12.006","DOIUrl":"https://doi.org/10.1016/j.jma.2024.12.006","url":null,"abstract":"A major problem facing the magnesium melting process is to address the oxidative combustion of magnesium. At present, there are still some problems in the method used to protect magnesium smelting. For example, the reaction of covering flux with magnesium melt is likely to produce a large number of toxic and harmful gasses (Cl<sub>2</sub> and HCl), the cost of such reaction is high, and there is a lack of clarity on the protection mechanism of CO<sub>2</sub> acting as the protective gas of magnesium melt. Therefore, a new process is proposed in this paper to isolate the air on the surface of magnesium melt using MgO-C-Mg film. Based on the thermodynamic theory of MgO-C-Mg film formation during crude magnesium smelting, an investigation is conducted into the effect of different experimental conditions on the protective effect of magnesium. Not only is the protective mechanism of MgO-C-Mg film revealed, it is also verified that the MgO-C-Mg film can produce a more pronounced protective effect at suitable temperature. According to thermodynamic analysis, magnesium melt reacts with CO<sub>2</sub> to form magnesium oxide and C. CO<sub>2</sub> consumes C when the experimental temperature exceeds 700 °C. This is contrary to the purpose of the experiment as it should be maintained at about 700 °C. The experimental results show that an obvious protective effect can be produced on the magnesium melt by the MgO-C-Mg film generated under the following conditions of 90% CO<sub>2</sub>–10% Ar, smelting temperature of 700 °C, holding time of 60 min, and stirring time of 20 min.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"6 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142917941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graphene, as the reinforcing phase of magnesium matrix composites, can effectively improve the material strength, elastic modulus, and other properties. However, the random distribution of graphene in the matrix (i.e., random orientation angle) leads to different reinforcement effects on the matrix. To gain a deeper understanding of the impact of monolayer graphene (1LG) with varying orientation angles on the properties of Mg-9Al-1Zn (AZ91 (wt.%)) magnesium alloy, molecular dynamics (MD) simulations are employed to analyze the mechanical properties of AZ91/1LG composites under uniaxial tension. The simulation results show that Young's modulus and tensile strength of AZ91/1LG composites decrease gradually with the increase of the orientation angle of the 1LG. The Young's modulus and tensile strength of AZ91/1LG composites can be improved by the 1LG orientation angle of 0°∼10° , where the two are enhanced by 21.7% and 19.7% respectively, at an orientation angle of 0°. However, the Young's modulus and tensile strength of 1LG are decreased for orientation angles of 20°∼90°. Atomic structure evolution analysis revealed that the deformation mechanism of AZ91/1LG nanocomposites mainly depended on the load transfer ability of 1LG with different orientation angles, the bonding ability with AZ91 magnesium alloy matrix and the change of dislocation density. By fitting the formula to the tensile strength of AZ91/1LG composites with different orientation angles of 1LG, it is found that the simulated data of the AZ91/1LG composites containing a 1LG has a maximum relative error of about 10% concerning the fitted empirical formula to calculate the data. The maximum relative error for AZ91/1LG composites containing multiplate 1LG with different orientation angles is 7%. In addition, the interaction between graphene and dislocations in AZ91 magnesium matrix was further explained by transmission electron microscopy (TEM) and phase-field-crystal (PFC) simulation. It can provide some technical guidance for the experimental process design of AZ91/1LG composites.
{"title":"Strengthening/weakening effect of graphene orientation angle on mechanical properties of AZ91 magnesium matrix composites","authors":"Dunwei Peng, Zhuo Song, Yunpeng Zhang, Xiaopan Wang, Hua Hou, Yuhong Zhao","doi":"10.1016/j.jma.2024.12.001","DOIUrl":"https://doi.org/10.1016/j.jma.2024.12.001","url":null,"abstract":"Graphene, as the reinforcing phase of magnesium matrix composites, can effectively improve the material strength, elastic modulus, and other properties. However, the random distribution of graphene in the matrix (i.e., random orientation angle) leads to different reinforcement effects on the matrix. To gain a deeper understanding of the impact of monolayer graphene (1LG) with varying orientation angles on the properties of Mg-9Al-1Zn (AZ91 (wt.%)) magnesium alloy, molecular dynamics (MD) simulations are employed to analyze the mechanical properties of AZ91/1LG composites under uniaxial tension. The simulation results show that Young's modulus and tensile strength of AZ91/1LG composites decrease gradually with the increase of the orientation angle of the 1LG. The Young's modulus and tensile strength of AZ91/1LG composites can be improved by the 1LG orientation angle of 0°∼10° , where the two are enhanced by 21.7% and 19.7% respectively, at an orientation angle of 0°. However, the Young's modulus and tensile strength of 1LG are decreased for orientation angles of 20°∼90°. Atomic structure evolution analysis revealed that the deformation mechanism of AZ91/1LG nanocomposites mainly depended on the load transfer ability of 1LG with different orientation angles, the bonding ability with AZ91 magnesium alloy matrix and the change of dislocation density. By fitting the formula to the tensile strength of AZ91/1LG composites with different orientation angles of 1LG, it is found that the simulated data of the AZ91/1LG composites containing a 1LG has a maximum relative error of about 10% concerning the fitted empirical formula to calculate the data. The maximum relative error for AZ91/1LG composites containing multiplate 1LG with different orientation angles is 7%. In addition, the interaction between graphene and dislocations in AZ91 magnesium matrix was further explained by transmission electron microscopy (TEM) and phase-field-crystal (PFC) simulation. It can provide some technical guidance for the experimental process design of AZ91/1LG composites.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"6 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142917943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The addition of ceramic reinforcements provides a promising approach to achieving high-performance magnesium matrix composites. In this work, AZ91D magnesium alloys and 2 wt.% TiC/AZ91D composites have been manufactured by laser powder bed fusion (LPBF) with variations of laser processing parameters. The effect of TiC reinforcement addition on the laser absorption behaviors, forming quality, microstructure evolution and mechanical properties of the magnesium alloys is investigated. The TiC addition improves the interactions of laser with alloy powder and laser absorption rate of alloy powder, and decreases powder spatter of powder bed. The results show that high relative density of ∼99.4 % and good surface roughness of ∼12 µm are obtained for the LPBF-fabricated composites. The TiC addition promotes the precipitation of β-Mg17Al12 in the alloys and the transformation of coarse columnar to fine equiaxed grains, where the grains are refined to ∼3.1 µm. The TiC/AZ91D composites exhibit high microhardness of 114.6 ± 2.5 HV0.2, high tensile strength of ∼345.0 MPa and a uniform elongation ∼4.1 %. The improvement of tensile strength for the composites is ascribed to the combination of grain refinement strengthening and Orowan strengthening from β-Mg17Al12 precipitates and Al8Mn5 nanoparticles. In the composites, the unmelted TiC particles can act as an anchor for the network structure of β-Mg17Al12 precipitates, effectively impeding crack propagation and enhancing their performance. This work offers an insight to fabricating high-performance magnesium matrix composites by laser additive manufacturing.
{"title":"Enhanced manufacturing quality and mechanical performance of laser powder bed fused TiC/AZ91D magnesium matrix composites","authors":"Lixia Xi, Songmao Tian, Jiongyu Jia, Zhi Zhong, Dong Zhang, Zhiming Li, Jiaxing Hou, Keyu Shi, Dongdong Gu","doi":"10.1016/j.jma.2024.12.012","DOIUrl":"https://doi.org/10.1016/j.jma.2024.12.012","url":null,"abstract":"The addition of ceramic reinforcements provides a promising approach to achieving high-performance magnesium matrix composites. In this work, AZ91D magnesium alloys and 2 wt.% TiC/AZ91D composites have been manufactured by laser powder bed fusion (LPBF) with variations of laser processing parameters. The effect of TiC reinforcement addition on the laser absorption behaviors, forming quality, microstructure evolution and mechanical properties of the magnesium alloys is investigated. The TiC addition improves the interactions of laser with alloy powder and laser absorption rate of alloy powder, and decreases powder spatter of powder bed. The results show that high relative density of ∼99.4 % and good surface roughness of ∼12 µm are obtained for the LPBF-fabricated composites. The TiC addition promotes the precipitation of β-Mg<sub>17</sub>Al<sub>12</sub> in the alloys and the transformation of coarse columnar to fine equiaxed grains, where the grains are refined to ∼3.1 µm. The TiC/AZ91D composites exhibit high microhardness of 114.6 ± 2.5 HV<sub>0.2</sub>, high tensile strength of ∼345.0 MPa and a uniform elongation ∼4.1 %. The improvement of tensile strength for the composites is ascribed to the combination of grain refinement strengthening and Orowan strengthening from β-Mg<sub>17</sub>Al<sub>12</sub> precipitates and Al<sub>8</sub>Mn<sub>5</sub> nanoparticles. In the composites, the unmelted TiC particles can act as an anchor for the network structure of β-Mg<sub>17</sub>Al<sub>12</sub> precipitates, effectively impeding crack propagation and enhancing their performance. This work offers an insight to fabricating high-performance magnesium matrix composites by laser additive manufacturing.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"97 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142924618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-30DOI: 10.1016/j.jma.2024.11.010
Dong Liang, Lipeng Wang, Tingzhuang Ma, Rong Yu, Yang Tian, Baoqiang Xu, Bin Yang
Magnesium (Mg), as one of the most abundant elements in earth's crust, is the lightest structural metal with extensive applications across various industries. However, the performance of Mg-based products is highly dependent on their impurity levels, and the lack of high-purity Mg, along with efficient purification method, has posed significant challenge to its widespread industrial adoption. This study investigates the impurity behavior in Mg ingots during the vacuum gasification purification process. Through the analysis of binary phase diagrams, iron (Fe)-based foam material was selected for the filtration and purification of Mg vapor in a vacuum tube furnace. A novel approach combining vacuum gasification, vapor purification, and directional condensation is proposed. The effect of filter pore sizes and filtration temperatures on the efficacy of impurity removal was evaluated. Experimental results demonstrate that Fe-based foam with a pore size of 60 ppi, at a filtration temperature of 773 K, effectively removes impurities such as calcium (Ca), potassium (K), sodium (Na), manganese (Mn), silicon (Si), aluminum (Al), and various oxides, sulfides, and chlorides from the vapor phase. Consequently, high-purity Mg with a purity level exceeding 5N3 was obtained in the condensation zone.
{"title":"Deep removal impurities in the process of preparing high-purity magnesium by vacuum gasification","authors":"Dong Liang, Lipeng Wang, Tingzhuang Ma, Rong Yu, Yang Tian, Baoqiang Xu, Bin Yang","doi":"10.1016/j.jma.2024.11.010","DOIUrl":"https://doi.org/10.1016/j.jma.2024.11.010","url":null,"abstract":"Magnesium (Mg), as one of the most abundant elements in earth's crust, is the lightest structural metal with extensive applications across various industries. However, the performance of Mg-based products is highly dependent on their impurity levels, and the lack of high-purity Mg, along with efficient purification method, has posed significant challenge to its widespread industrial adoption. This study investigates the impurity behavior in Mg ingots during the vacuum gasification purification process. Through the analysis of binary phase diagrams, iron (Fe)-based foam material was selected for the filtration and purification of Mg vapor in a vacuum tube furnace. A novel approach combining vacuum gasification, vapor purification, and directional condensation is proposed. The effect of filter pore sizes and filtration temperatures on the efficacy of impurity removal was evaluated. Experimental results demonstrate that Fe-based foam with a pore size of 60 ppi, at a filtration temperature of 773 K, effectively removes impurities such as calcium (Ca), potassium (K), sodium (Na), manganese (Mn), silicon (Si), aluminum (Al), and various oxides, sulfides, and chlorides from the vapor phase. Consequently, high-purity Mg with a purity level exceeding 5N3 was obtained in the condensation zone.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"83 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142902149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-23DOI: 10.1016/j.jma.2024.11.031
Lipeng Wang, Dong Liang, Rong Yu, Meng Wang, Yang Tian, Tingzhuang Ma, Bin Yang, Baoqiang Xu, Wenlong Jiang
Magnesium (Mg) alloy is widely used in aerospace and automotive industries as an excellent lightweight metal material to reduce carbon emissions. The expansion of Mg alloy applications and the increasing demands for these materials have significantly facilitated the generation of Mg alloy scrap. The recycling of Mg resources is crucial for promoting both environmental sustainability and economic viability. However, current recycling effect is unsatisfactory. Therefore, this paper provides a comprehensive review of the entire recycling process, including scrap classification, separation and sorting, pre-treatment, and recycling. This paper explores the generation of Mg alloy scrap and its reincorporation into industrial products. This review outlines various Mg scrap recycling technologies based on different phase states. These include liquid-state recycling (such as flux refining, impurity removal additives, fluxless refining, compound treatment, and direct remelting), solid-state recycling (involving hot extrusion, equal-channel angular pressing (ECAP), friction stir extrusion (FSE), and spark plasma sintering (SPS)), vapor-state recycling (comprising vacuum distillation and sublimation), electrochemical recycling (solid oxide membrane (SOM) electrolysis, RE-12™ electrorefining, and non-aqueous solution electrorefining), and Mg secondary alloy development. The advantages and existing challenges associated with each method are compared and discussed, and the current obstacles to the future recycling of complex scrap are examined.
{"title":"Progress and prospects in magnesium alloy scrap recycling","authors":"Lipeng Wang, Dong Liang, Rong Yu, Meng Wang, Yang Tian, Tingzhuang Ma, Bin Yang, Baoqiang Xu, Wenlong Jiang","doi":"10.1016/j.jma.2024.11.031","DOIUrl":"https://doi.org/10.1016/j.jma.2024.11.031","url":null,"abstract":"Magnesium (Mg) alloy is widely used in aerospace and automotive industries as an excellent lightweight metal material to reduce carbon emissions. The expansion of Mg alloy applications and the increasing demands for these materials have significantly facilitated the generation of Mg alloy scrap. The recycling of Mg resources is crucial for promoting both environmental sustainability and economic viability. However, current recycling effect is unsatisfactory. Therefore, this paper provides a comprehensive review of the entire recycling process, including scrap classification, separation and sorting, pre-treatment, and recycling. This paper explores the generation of Mg alloy scrap and its reincorporation into industrial products. This review outlines various Mg scrap recycling technologies based on different phase states. These include liquid-state recycling (such as flux refining, impurity removal additives, fluxless refining, compound treatment, and direct remelting), solid-state recycling (involving hot extrusion, equal-channel angular pressing (ECAP), friction stir extrusion (FSE), and spark plasma sintering (SPS)), vapor-state recycling (comprising vacuum distillation and sublimation), electrochemical recycling (solid oxide membrane (SOM) electrolysis, RE-12™ electrorefining, and non-aqueous solution electrorefining), and Mg secondary alloy development. The advantages and existing challenges associated with each method are compared and discussed, and the current obstacles to the future recycling of complex scrap are examined.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"24 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density, Mg−RE−TM (RE = rare earth, TM = metallic element) alloys have been extensively researched and hold great promise. In this study, a series of Mg−RE−TM based Mg90Y2Ce2Ni3Al3-xScx (x = 0, 0.3, 0.6, 0.9, 1.2) alloys were prepared. The addition of Sc element has been found to enhance the activation and kinetic properties of the alloy. Compared with the significant differences in the first four dehydrogenation curves of the Sc0 sample, the first activated dehydrogenation curve of the Sc1.2 alloy overlaps with the fully activated dehydrogenation curve. The dehydrogenation activation energy decreased from 96.56 kJ/mol in the Sc0 alloy to 63.69 kJ/mol in the Sc0.9 alloy. Through analysis of the microstructure, phase composition, and hydrogen absorption and desorption kinetics of the alloy, the mechanisms for improving the hydrogen storage properties of the alloy were elucidated. The nucleation-growth-impingement Avrami model was employed to accurately simulate the hydrogen storage kinetics. The results showed that stage II was prolonged and accelerated at high temperature, and the growth rate and hydrogen storage of stage I were increased at low temperature in hydrogen absorption. Microstructure analysis revealed the presence of Mg, CeMg12, Mg47Y, and YNi2Al3 phases in the Sc0 sample. Upon the addition of Sc element, a new phase, ScNiAl, was formed, and the coarse grain size of the main phase was significantly refined. This refinement provides faster diffusion channels for hydrogen atoms, accelerating the phase transition between Mg alloys and hydrides. The microstructure changes explain the improved activation properties, effective hydrogen absorption and desorption capacity, and kinetic properties of the Mg-based samples.
{"title":"Modifying hydrogen storage properties of the RE−Mg-based alloys with minor Sc addition","authors":"Hanfeng Sun, Peng Sheng, Jun Li, Shihai Guo, Qilu Ge, Yanghuan Zhang","doi":"10.1016/j.jma.2024.11.034","DOIUrl":"https://doi.org/10.1016/j.jma.2024.11.034","url":null,"abstract":"To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density, Mg−RE−TM (RE = rare earth, TM = metallic element) alloys have been extensively researched and hold great promise. In this study, a series of Mg−RE−TM based Mg<sub>90</sub>Y<sub>2</sub>Ce<sub>2</sub>Ni<sub>3</sub>Al<sub>3-</sub><em><sub>x</sub></em>Sc<em><sub>x</sub></em> (<em>x</em> = 0, 0.3, 0.6, 0.9, 1.2) alloys were prepared. The addition of Sc element has been found to enhance the activation and kinetic properties of the alloy. Compared with the significant differences in the first four dehydrogenation curves of the Sc0 sample, the first activated dehydrogenation curve of the Sc1.2 alloy overlaps with the fully activated dehydrogenation curve. The dehydrogenation activation energy decreased from 96.56 kJ/mol in the Sc0 alloy to 63.69 kJ/mol in the Sc0.9 alloy. Through analysis of the microstructure, phase composition, and hydrogen absorption and desorption kinetics of the alloy, the mechanisms for improving the hydrogen storage properties of the alloy were elucidated. The nucleation-growth-impingement Avrami model was employed to accurately simulate the hydrogen storage kinetics. The results showed that stage II was prolonged and accelerated at high temperature, and the growth rate and hydrogen storage of stage I were increased at low temperature in hydrogen absorption. Microstructure analysis revealed the presence of Mg, CeMg<sub>12</sub>, Mg<sub>47</sub>Y, and YNi<sub>2</sub>Al<sub>3</sub> phases in the Sc0 sample. Upon the addition of Sc element, a new phase, ScNiAl, was formed, and the coarse grain size of the main phase was significantly refined. This refinement provides faster diffusion channels for hydrogen atoms, accelerating the phase transition between Mg alloys and hydrides. The microstructure changes explain the improved activation properties, effective hydrogen absorption and desorption capacity, and kinetic properties of the Mg-based samples.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"85 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.1016/j.jma.2024.12.010
Xingjian Zhao, Daniel Olden, Brady Williams, Abhishek Pariyar, Dalong Zhang, Matthew Murphy, Philippa Reed, Paul Allison, Brian Jordon, Jiahui Qi, W. Mark Rainforth, Dikai Guan
Ultrafine-grained (UFG) materials exhibit high strengths due to grain boundary strengthening, but grains can grow rapidly if post heat treatment is required, making it challenging to achieve grain boundary and precipitation strengthening simultaneously. Grain growth stagnation at 525 °C (0.87 Tm, melting point) was observed in a Mg-4Y-3RE alloy fabricated by additive friction stir deposition (AFSD), a novel solid-state additive manufacturing technology. The AFSD processing produced a UFG microstructure and two major second phases, Mg41RE5 and nanoparticles containing Y and O. After solid solution treatment (SST) at 525 °C for 72 h, no noticeable grain growth occurred. While Mg41RE5 particles dissolved into the matrix within 4 h of SST, the nanoparticles remained stable and unaltered. The observed grain growth stagnation is attributed to Zener pinning by these thermally stable nanoparticles. These new findings offer a novel approach to designing UFG materials with exceptional thermal stability for high-temperature applications.
{"title":"Grain growth stagnation at 525 °C by nanoparticles in a solid-state additively manufactured Mg-4Y-3RE alloy","authors":"Xingjian Zhao, Daniel Olden, Brady Williams, Abhishek Pariyar, Dalong Zhang, Matthew Murphy, Philippa Reed, Paul Allison, Brian Jordon, Jiahui Qi, W. Mark Rainforth, Dikai Guan","doi":"10.1016/j.jma.2024.12.010","DOIUrl":"https://doi.org/10.1016/j.jma.2024.12.010","url":null,"abstract":"Ultrafine-grained (UFG) materials exhibit high strengths due to grain boundary strengthening, but grains can grow rapidly if post heat treatment is required, making it challenging to achieve grain boundary and precipitation strengthening simultaneously. Grain growth stagnation at 525 °C (0.87 T<sub>m</sub>, melting point) was observed in a Mg-4Y-3RE alloy fabricated by additive friction stir deposition (AFSD), a novel solid-state additive manufacturing technology. The AFSD processing produced a UFG microstructure and two major second phases, Mg<sub>41</sub>RE<sub>5</sub> and nanoparticles containing Y and O. After solid solution treatment (SST) at 525 °C for 72 h, no noticeable grain growth occurred. While Mg<sub>41</sub>RE<sub>5</sub> particles dissolved into the matrix within 4 h of SST, the nanoparticles remained stable and unaltered. The observed grain growth stagnation is attributed to Zener pinning by these thermally stable nanoparticles. These new findings offer a novel approach to designing UFG materials with exceptional thermal stability for high-temperature applications.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"64 1","pages":""},"PeriodicalIF":17.6,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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