Article
Nanoscience & Nanotechnology
Anette B. Hagen, Sigurd Wenner, Ruben Bjorge, Di Wan, Calin D. Marioara, Randi Holmestad, Inga G. Ringdalen
Summary: Al-Mg-Si (6xxx series) alloys exhibit strong mechanical properties but are weakened by a soft precipitation free zone (PFZ) near grain boundaries during heat treatment, reducing material ductility. This study employs nanoindentation and microstructure characterization to quantitatively analyze these alloys. Experimental results confirm that the PFZ weakens the material, while an adjacent region exhibits increased hardness due to a higher density of precipitates. This previously unrecognized harder zone has important implications for the mechanical properties of large-grained aluminum alloys.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Mingjun Yang, Andrey Orekhov, Zhi-Yi Hu, Man Feng, Shenbao Jin, Gang Sha, Kai Li, Vahid Samaee, Min Song, Yong Du, Gustaaf Van Tendeloo, Dominique Schryvers
Summary: In-situ TEM experiments revealed that coherent beta'' precipitates in Al alloys are sheared into small fragments by dislocations, while semi-coherent beta' precipitates are more difficult to be fragmented and can maintain their shape after tensile deformation.
Article
Materials Science, Multidisciplinary
Changping Tang, Kai Wu, Wenhui Liu, Di Feng, Guoliang Zuo, Wuying Liang, Yue Yang, Xu Chen, Quan Li, Xiao Liu
Summary: The study found that peak-aged samples exhibit the highest compressive strength, while the dynamic compressive strength of the as-extruded sample is sensitive to strain rates. The high strength is mainly attributed to dynamic precipitates and work hardening effect caused by dislocations.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Dongsheng Xie, Hucheng Pan, Yu Huang, Dongdong Zhang, Weineng Tang, Chubin Yang, Hongbo Xie, Yuping Ren, Gaowu Qin
Summary: This study systematically investigated the microstructure and mechanical properties of an extruded Mg-Ca-Mn based alloy at different temperatures. Samples extruded at low temperatures exhibited ultra-high yield strength and limited elongation, while those extruded at high temperatures showed higher ultimate tensile strength at elevated temperatures. Solute segregation at grain boundaries played a crucial role in enhancing high temperature strength.
MATERIALS CHARACTERIZATION
(2022)
Article
Metallurgy & Metallurgical Engineering
Hui Shi, Yuanding Huang, Lixiang Yang, Chunquan Liu, Hajo Dieringa, Chong Lu, Lv Xiao, Regine Willumeit-Roemer, Norbert Hort
Summary: This study investigates the creep behavior and microstructural evolution of sand-cast Mg-14Gd-0.4Zr alloy using compressive creep tests. The results show that the coherent distribution of beta' and beta' (F) phases effectively impedes dislocation movement and enhances creep resistance. However, with increasing creep time, the fine precipitate chains coarsen and transform into different phases, leading to stress concentration and increased creep strain.
JOURNAL OF MAGNESIUM AND ALLOYS
(2023)
Article
Materials Science, Multidisciplinary
Yun Feng, Yuanyuan Yang, Zongqi Xiao, Xianglong Meng, Guorong Zhou, Jinfeng Leng, Xinying Teng
Summary: The influence of aluminum on the mechanical properties and microstructure of Mg-Sn-Ca-Mn alloys was systematically investigated, and the addition of 1.5 wt% Al significantly increased the yield strength of the alloy. The extruded alloy exhibited a bimodal grain structure with dynamic recrystallized fine grains and coarse unrecrystallized grains. Additionally, the alloy with 1.5 wt% Al showed a significant enhancement in fiber texture.
METALS AND MATERIALS INTERNATIONAL
(2022)
Article
Chemistry, Physical
Yifan Wang, Yanli Lu, Shiyao Zhang, Haipeng Zhang, Hong Wang, Zheng Chen
Summary: Through TEM and tensile testing, the microstructure of nanoscale precipitates formed in the primary a-Al grains of a cast Al-7Si-Mg alloy during ageing at different temperatures has been systematically investigated. The interactions of dislocations with different types of precipitates were analyzed, revealing the strengthening effects on mechanical properties. The study also discussed the moire fringes and FFT pattern of beta phase, as well as the unique phenomenon of beta phase nucleation and growth on the surface of Si particles.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Xinyu Sun, Chuncheng Ge, Chubin Yang, Dongdong Zhang, Jingren Li, Dongsheng Xie, Hucheng Pan, Gaowu Qin
Summary: In this study, the microstructure and mechanical properties of Mg alloys were investigated. It was found that specific combinations of alloys can achieve ultra-high strength and high thermal stability. The deformed grains and residual dislocation density during extrusion, as well as the nano-precipitates induced by manganese addition, play important roles in the performance of the alloys.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
Jingyu Jiang, Feng Jiang, Menghan Zhang, Zhongqin Tang, Mengmeng Tong
Summary: The Al-6 Mg-0.4Mn-0.25Sc-0.1Zr extrusion rod underwent ECAP treatment to achieve nonuniform structure. After annealing at different temperatures, it was observed that the hardness of the samples decreased, with the 1P sample experiencing a faster decrease compared to the 0P sample, resulting in a hardness "upside down" phenomenon. The drastic recrystallization induced by high strain in the shear band was identified as the cause of these phenomena.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Kun Yang, Hucheng Pan, Sen Du, Man Li, Jingren Li, Hongbo Xie, Qiuyan Huang, Huajun Mo, Gaowu Qin
Summary: A novel low-cost Mg-Al-Ca-Zn-Mn-based alloy has been developed to enhance both strength and ductility. The alloy exhibits high yield strength and elongation to failure, attributed to the ultra-fined dynamically recrystallized grains and high-density dislocations and nano-precipitates in the un-DRXed region.
INTERNATIONAL JOURNAL OF MINERALS METALLURGY AND MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Li Zhao, Jianqiang Hao, Cuirong Liu, Zhisheng Wu, Jinshan Zhang, Hongxia Wang, Weili Cheng
Summary: By adding an appropriate amount of B4C, the Mg94Zn2.5Y2.5Mn1 alloy showed refined grains, promotion of LPSO phase formation, inhibition of W phase generation, and significant improvement in mechanical properties.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Xinkui Zhang, Liejun Li, Zhi Wang, Hanlin Peng, Jixiang Gao, Zhengwu Peng
Summary: This study developed a novel near-eutectic Al-La alloy with significant strengthening and work hardening ability through selective laser melting. The alloy exhibited high tensile yield strength and ultimate tensile strength at room temperature.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Hansong Xue, Song Liu, Wei Xie, Yang Zhou, Jianbo Peng, Haitao Pan, Dingfei Zhang, Fusheng Pan
Summary: The effects of different Dy additions on the microstructure and mechanical properties of Mg-6Zn-1Mn-3Sn (wt%, ZMT613) alloys were investigated. The study found that Dy addition resulted in significant grain refinement and the formation of new MgSnDy phases. A small amount of Dy (≤0.8 wt%) hindered the proportion of dynamic recrystallized grains during the hot-extrusion process and enhanced the basal texture of the alloy. MgSnDy high-temperature phase particles inhibited the recovery process and promoted the precipitation of the second phase. The ZMT613-0.2Dy alloy showed optimum mechanical properties after aging, with yield strength, ultimate tensile strength, and elongation reaching 336 MPa, 399 MPa, and 4.4%, respectively.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
Chongchen Xiang, Zhuo Huang, Zijian Wang, Hanlin Ding, Shun Xu
Summary: In this paper, Cu alloying was used to study Mg-Al-Ca-Mn-Cu magnesium alloys, aiming to develop magnesium alloys with higher heat conduction. The mechanical properties and thermal conductivity of the alloys were evaluated simultaneously due to the addition of Cu, meeting the requirements of developing high-strength and high-conductivity magnesium alloys. Compared with the commercial AZ31 magnesium alloy, the strength and plasticity of the alloys were improved through fine grain strengthening. Meanwhile, the amount of solid solution atoms in the alloy decreased and the content of the second phase particles increased, leading to a reduced degree of lattice distortion. On the other hand, the Cu element provided a large amount of free electrons for heat transfer, resulting in high thermal conductivity for the alloys.
MATERIALS CHARACTERIZATION
(2023)
Article
Chemistry, Physical
Chao Sun, Huan Liu, Ce Wang, Jia Ju, Guowei Wang, Jinghua Jiang, Aibin Ma, Jing Bai, Feng Xue, Yunchang Xin
Summary: This study investigated the anisotropy of a 32-pass ECAP processed Mg-3.7Al-1.8Ca-0.4Mn alloy, which exhibited synergistically enhanced mechanical properties and corrosion resistance. The ECAP alloy had homogeneous fine alpha-Mg grains and different distribution of refined Al2Ca particles. The refinement of microstructure resulted in the formation of a protective film on the ECAP alloy, leading to different corrosion mechanisms compared to the as-cast alloy. The distribution of Al2Ca and the texture of alpha-Mg were identified as the main factors affecting the anisotropic properties of the ECAP alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Metallurgy & Metallurgical Engineering
T. Nakata, C. Xu, K. Kaibe, Y. Yoshida, K. Yoshida, S. Kamado
Summary: Strength and ductility of an Mg-3%Al-Mn alloy sheet were improved using twin-roll casting and low-temperature annealing, resulting in excellent tensile properties and stretch formability.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Nanoscience & Nanotechnology
T. Nakata, C. Xu, Y. Ito, S. Kamado
Summary: The effect of homogenization on microstructures and tensile properties in a dilute Mg-Zn-Ca-Mn alloy sheet was investigated. High-temperature homogenization dissolved eutectic intermetallic phases before rolling, but led to significant growth of alpha Mn precipitates and coarse grain structure after rolling and annealing. Rolling without homogenization or after low-temperature homogenization resulted in increased fraction of intermetallic phases, but achieved a fine grain structure due to dispersed alpha Mn precipitates.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Huafeng Liu, Jing Zuo, Taiki Nakata, Chao Xu, Guisong Wang, Hailong Shi, Guangze Tang, Xiaojun Wang, Shigeharu Kamado, Lin Geng
Summary: The effects of La addition on the microstructure, thermal conductivity, and mechanical properties of Mg-3Al-xLa-0.3Mn alloys in as-cast and as-extruded states were investigated. The results showed that the addition of La element led to an increase in thermal conductivity due to the formation of Al11La3 phases. However, the as-extruded alloys exhibited lower thermal conductivity compared to the as-cast alloys due to the presence of defects, particularly at the grain boundaries. The anisotropy of thermal conductivity was observed in the as-extruded alloys as a result of texture formation. The tensile and yield strength of the as-extruded alloys decreased with increasing La content, while the elongation initially increased and then decreased due to the combined effects of texture strengthening and second phase strengthening.
Article
Nanoscience & Nanotechnology
T. Nakata, C. Xu, K. Sugiya, Y. Yoshida, K. Yoshida, L. Geng, S. Kamado
Summary: An anomalous in-plane anisotropy was observed in a basal-textured Mg-Al-Zn alloy sheet due to the high activation of tensile twinning induced by a small fraction of transverse direction (TD)-oriented (0001) poles. This led to deteriorated tensile properties along the TD, emphasizing the importance of microtexture design for high-performance wrought magnesium.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Jing Zuo, Mingquan Zhang, Taiki Nakata, Guisong Wang, Danyang Li, Hailong Shi, Chao Xu, Xiaojun Wang, Wenjun Li, Guohua Fan, Lin Geng, Shigeharu Kamado
Summary: In this study, we investigated the effect of 0-1.0 at.% Al additions on grain refinement and phase transformation of the Mg-2.0Gd-1.2Y-0.5Zn-0.2Mn alloy containing LPSO phase. The addition of Al promoted the formation of the Al2RE phase and decreased the presence of LPSO phase and Mg3RE phase. The Al2RE phase acted as nucleants for α-Mg grains, resulting in a significant decrease in grain size.
Article
Materials Science, Multidisciplinary
Shiwei Xu, Congcong Zhu, S. Kamado, K. Oh-ishi, Yun Qin
Summary: This study systematically investigates the dynamic recrystallization behavior of as-cast AZ91 magnesium alloy under hot compression deformation at 350 degrees C. The results show that multiple DRX mechanisms, including twinning, grain boundary bulging, and particle-stimulated nucleation, are observed at 350 degrees C. Continuous DRX is the dominant mechanism at this temperature. Compared to hot compression at 300 degrees C, the DRX grain size and volume fraction increase after hot compression at 350 degrees C.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
J. Zuo, T. Nakata, C. Xu, Y. P. Xia, H. L. Shi, G. S. Wang, G. Z. Tang, G. H. Fan, S. Kamado, L. Geng
Summary: The microstructure evolution and mechanical properties of the as-drawn dilute Mg-0.8Al-0.1Ca-0.6Mn alloy wires during annealing and peak-aging treatment were investigated. The study revealed that the high density of nano-sized Al-Mn precipitates hindered grain boundary migration and restricted grain growth during low-temperature annealing, while partial dissolution of Al-Mn precipitates led to obvious grain growth and increased uniformity of recrystallization grain size during high-temperature annealing. Additionally, there was a growth preference in grains with a specific orientation, which was closely associated with texture changes. Furthermore, the alloy exhibited a significant age-hardening response after peak-aging treatment at 500 degrees C for 10 minutes, resulting in simultaneous improvement of tensile yield strength and elongation to failure, which was mainly attributed to the formation of monolayered Guinier-Preston (G.P.) zones and planar Al2Ca precipitates.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
T. Nakata, Z. H. Li, T. T. Sasaki, K. Hono, S. Kamado
Summary: This study reports the influence of grain boundary segregation on microstructure development during hot-rolling of AZ31 alloy. Annealing at 420 degrees C induces strong grain boundary segregation, promoting dynamic recrystallization and strong basal texture. Annealing at 500 degrees C reduces grain boundary segregation, hindering dynamic recrystallization and resulting in a weak rolling-direction-split texture, improving the stretch formability of the alloy sheet.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Physical
Zhao Yang, Taiki Nakata, Chao Xu, Gang Wang, Lin Geng, Shigeharu Kamado
Summary: A high-performance Mg-8Gd-4Y-0.5Mn-0.2Sc alloy was fabricated using homogenization, hot extrusion, and ageing. The microstructure evolution during homogenization was studied, and an optimum time of 18 h was determined to minimize the volume fraction of second phase particles and maintain a fine grain structure. The alloy exhibited excellent age-hardening ability and strength after peak-aged treatment, with a tensile yield stress of 441 MPa and an ultimate tensile strength of 506 MPa. The high yield strength was attributed to the co-existing bimodal microstructure, fine dynamically recrystallized grains, dense precipitated particles, and nano-scale precipitates. Precipitation strengthening was revealed as the dominant strengthening mechanism.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
T. Nakata, C. Xu, L. Geng, S. Kamado
Summary: This paper reports the application of cold-sample rolling (CSR) processing in a Mg-6Al-1Zn alloy sheet, which resulted in a high fraction of double twins and a substantial texture-weakening effect. Compared to high-temperature rolling (HTR) processing, CSR processing induced a relatively higher texture-weakening effect. The results indicate that twinning-mediated static recrystallization is essential for texture weakening in Al-concentrated Mg-alloy sheets.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Shiwei Xu, Congcong Zhu, Zhanhong Lin, Chen Jin, S. Kamado, K. Oh-ishi, Yun Qin
Summary: The dynamic microstructure and texture of dilute Mg-0.50Al-0.71Ca-0.33Mn alloy during hot rolling were investigated. The study revealed the important role of extension twins, double twins, and kinks in the formation of rolling texture.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Nanoscience & Nanotechnology
Z. H. Li, S. Gao, T. T. Sasaki, T. Nakata, S. Kamado, N. Tsuji, K. Hono
Summary: Clarifying the origin of the yielding phenomenon is crucial for improving the flow stability and surface finish of magnesium alloy sheet products. This study investigates the effect of Zn addition on discontinuous yielding in low-alloyed magnesium alloy sheets and reveals the significant impact of Zn on yield-drop. Transmission electron microscopy and atom probe tomography analysis demonstrate the influence of Ca-Zn co-clusters on dislocations, and different stretching directions of the sheet result in distinct Luders deformations.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Zhao Yang, Gang Wang, Chao Xu, Miao Wang, Taiki Nakata, Hongyu Xu, Lin Geng, Shigeharu Kamado
Summary: In this study, Mg-Gd-Y-Mn-Sc alloys with different Mn and Sc contents were prepared. The addition of Mn and Sc refined the grain size and promoted the dynamic recrystallization and dynamic precipitation during hot extrusion, resulting in improved strength-ductility balance of the alloy.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Chemistry, Physical
T. Nakata, T. Matsuno, R. Oki, S. Kamado
Summary: The effect of micro-texture on the tensile properties and room-temperature stretch formability of Mg-Al-Zn alloy sheet was studied. The introduction of micro-texture through solution treatment, hot-rolling, and post-annealing increased the fraction of a unique texture component, which improved the limiting dome height without compromising the strength due to the high activity of tensile twinning and minimal change in the Schmid factor for basal slips. This finding highlights the importance of micro-texture designing for the development of high strength-formability synergy in magnesium alloy sheets.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Crystallography
Tomoyuki Homma, Takashi Washizu
Summary: The beta-type and sintered Ti-3.6Fe-5Zr-0.2B alloy was consolidated using spark plasma sintering and followed by a beta solution treatment. Modification of sintering conditions improved the tensile ductility by achieving 100% relative density. Water quenching resulted in the formation of alpha martensite phases, while air cooling suppressed their formation and instead precipitated bimodal alpha lath phases, resulting in higher strength and better ductility.
Article
Materials Science, Multidisciplinary
Nizar Lefi, Salem Neily, Roland Bonnet
Summary: This paper investigates the elastic field in a bi-material crystal with an angular dislocation line with one branch placed in the crystal and the other along a strongly bound or welded interface. The analysis formulates the elastic field of a closed dislocation loop and solves it using the knowledge of the Green's tensor of the bi-material. The study provides a faster calculation method and has important implications for solving interfacial angular dislocation problems.
PHILOSOPHICAL MAGAZINE
(2024)
