Article
Metallurgy & Metallurgical Engineering
Yoshihiro Nagata, Kiyotaka Kato, Takuma Shishido, Ao Tsuchiya, Sanji Kitaoka, Naoto Oshiro, Naomi Nishi, Naoki Nonaka, Takayuki Koike, Toshimitsu Oike, Kenji Hayashi, Hiroshi Kambe, Toshimitsu Okane, Khairi Faiz Muhammad, Makoto Yoshida
Summary: This study aims to develop an Al-Mg alloy with both high ductility and low hot tearing susceptibility (HTS) by investigating the effects of additional elements on the alloy's mechanical properties and the mechanism of decreasing HTS. It was found that the co-addition of 0.025%Sr, 0.08%Ti, and 0.016%B reduced HTS and met the requirements for automotive structural parts. The decrease in HTS by the Sr addition was attributed to the formation of hydrogen porosity at a lower solid fraction.
INTERNATIONAL JOURNAL OF METALCASTING
(2023)
Article
Metallurgy & Metallurgical Engineering
Yongqiang Chen, Zheng Liu, Shimeng Liu, Hui Guo, Jia Liu, Xiaofang Sheng
Summary: Based on the modified Clyne-Davies model and the T-type hot tearing test system, the hot tearing susceptibility of Al-6Zn-2.5Mg-xCu (x = 0, 1, 2, 3 wt%) alloy was predicted and verified. It was found that the hot tearing susceptibility first decreased and then increased with the increase in the content of Cu, and the smallest was at the content of 2 wt%. Results also showed that the lower T-coh and T-hi, the lower the hot tearing susceptibility of alloys. The cooling structure of Al-6Zn-2.5Mg-2Cu alloy with the lowest hot tearing susceptibility corresponds to the finest grains, and a suitable amount of S (Al2CuMg) and T (Al2Mg3Zn3) phases is distributed on the grain boundary based on the analysis of different Cu contents on the crystallization of the parent phase and the precipitation of the second phase.
INTERNATIONAL JOURNAL OF METALCASTING
(2021)
Article
Metallurgy & Metallurgical Engineering
Bo Yu, Ruifeng Dou, Yifan Wang, Junsheng Wang, Xunliang Liu, Zhi Wen
Summary: Hot tearing is a severe defect in the casting process. The RDG criterion, which includes all strains in three directions, was improved to accurately predict hot tearing susceptibility. The improved RDG criterion showed optimal prediction accuracy and consistency with experimental results. Additionally, suitable casting and mold preheating temperatures were found to reduce hot tearing susceptibility.
INTERNATIONAL JOURNAL OF METALCASTING
(2023)
Article
Materials Science, Multidisciplinary
Bo Hu, Zixin Li, Dejiang Li, Tao Ying, Xiaoqin Zeng, Wenjiang Ding
Summary: A criterion based on solidification microstructure was proposed to predict the hot tearing behavior of cast alloys, considering various factors. The credibility of this criterion was validated through the study of hot tearing behavior of Mg-Ce alloys, and a simplified criterion and hot tearing index for specific cases were derived and validated.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Review
Materials Science, Multidisciplinary
Yue Li, Hongxiang Li, Laurens Katgerman, Qiang Du, Jishan Zhang, Linzhong Zhuang
Summary: This article reviews the development of hot tearing in aluminium alloys, explaining the phenomenon and mechanism, characterising the mechanical properties and susceptibility, providing data on mushy zone behavior, examining the impact of composition and casting parameters, describing hot tearing simulations, and making recommendations for further research development.
PROGRESS IN MATERIALS SCIENCE
(2021)
Article
Engineering, Industrial
Longfei Li, Ruijie Zhang, Qiangqiang Yuan, Shiyao Huang, Haitao Jiang
Summary: This study developed an integrated approach to study the hot tearing behavior of cast aluminum alloys by determining the constitutive behavior and rheological properties of the solidifying aluminum alloys using phase-field simulations and micromechanical calculations. An elastic-viscoplastic (E-VP) constitutive model was constructed for thermal stress analysis and hot tearing prediction. Experimental verification and establishment of a deformation mechanism of the solidifying mushy zone were also conducted. The study suggests that the constructed EVP model enables high-accuracy hot tearing predictions and is consistent with the deformation mechanism of the solidifying mushy zone. This comprehensive study on aluminum alloy castings provides a reference and integrated approach for multi-scale analysis in casting processing.
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2022)
Article
Chemistry, Physical
Yongtao Xu, Zhifeng Zhang, Zhihua Gao, Yuelong Bai, Purui Zhao, Weimin Mao
Summary: The addition of refiner Sc to the high Zn/Mg ratio 7xxx series aluminum alloy melt significantly reduces hot cracking sensitivity, decreases grain size, and improves mechanical properties such as tensile strength and elongation rate.
Article
Materials Science, Multidisciplinary
Mohammad Pourgharibshahi, Giulio Timelli
Summary: Computer-aided thermal analysis and phase diagram calculation were conducted using the ThermoCalc software to investigate the solidification path of an Al7.8Zn2.6Mg2Cu alloy. The study revealed the formation mechanism and effects of the main secondary phases, including Al6(Fe,Cu), Mg2Si, and Mg(Zn,Cu,Al)2. A four-step surface segregation-mediated description was proposed to explain the formation of these phases and their impact on the hot-tearing susceptibility of the alloy.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Khalil Ganjehfard, Reza Taghiabadi, Mohammad Talafi Noghani, Mohammad Hossein Ghoncheh
Summary: This study found that in cast Al-Cu alloys, the optimal tensile properties and hot tearing resistance were achieved at a Fe/Si mass ratio of 1, with detrimental effects observed for ratios above or below unity. The presence of beta-CuFe platelets and Si needles/micropores in the microstructure influenced the alloy's performance in tensile strength and hot tearing resistance.
INTERNATIONAL JOURNAL OF MINERALS METALLURGY AND MATERIALS
(2021)
Article
Chemistry, Physical
Rohit Shandley, A. Srinivasan, Appala Naidu Gandi, K. R. Ravi
Summary: In this study, the hot tearing susceptibility of Mg-10Gd-xZn was evaluated using the Kou model and compared with the experimental results obtained from the CRC test. The Kou-thermal analysis model showed good agreement with the experimentally obtained crack volume, while the Kou-TCMG5 model deviated from the experimental observations. The actual phase equilibria were found to be important in accurately predicting the hot tearing susceptibility using the Kou model.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Metallurgy & Metallurgical Engineering
P. V. Sai Divya, P. K. Penumakala, A. K. Nallathambi
Summary: Hot tears are a major challenge in the DC casting process, and a pore fraction based hot tearing model is applied to assess the hot tearing sensitivity of AZ31 billet. The study shows that the casting speed has a significant impact on pore fractions, with higher casting speeds leading to greater susceptibility to hot tearing.
TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS
(2023)
Article
Materials Science, Multidisciplinary
Pramote Thirathipviwat, Sega Nozawa, Moe Furusawa, Yusuke Onuki, Makoto Hasegawa, Katsushi Matsumoto, Shigeo Sato
Summary: The texture evolution and dislocation density in Al-Mg alloys during uniaxial tensile deformation were investigated using neutron diffraction experiment. The (001) and (111) duplex texture were observed in Al-Mg alloys under low strain rate (1.33 x 10-5 s-1). The differences in pole density at (001) and (111) orientations depended on the content of Mg addition. The (001) deformation texture was developed from initial (001) cube texture, especially in alloys with low Mg addition and pure Al sample. In alloys with high Mg addition, the development of (111) texture was clearly presented. An increase in Mg addition induced larger dislocation density during deformation in correlation with the formation of (111) deformation texture.
Article
Metallurgy & Metallurgical Engineering
Mohammad Pourgharibshahi, Hassan Saghafian, Mehdi Divandari, Farrokh Golestannejad
Summary: It was found that the susceptibility of aluminum alloy AA 7068 to hot tearing is strongly influenced by the solidification of the eutectic liquid at the film stage and solid feeding mechanisms. The formation of an absorbed eutectic layer on the primary phase is proposed to explain the loss of ductility and advance eutectic solidification. Increasing the back-diffusion rate through the CDS process can mitigate hot-tearing susceptibility by avoiding the formation of the adsorbed solid layer.
INTERNATIONAL JOURNAL OF METALCASTING
(2022)
Article
Materials Science, Multidisciplinary
Hyongjoon Lee, Hobyung Chae, You Sub Kim, Min Ji Song, Sangyeob Lim, Kali Prasad, Hariharan Krishnaswamy, Jayant Jain, Ke An, Soo Yeol Lee
Summary: The study found that AA7075 alloy in different heat treatment states exhibits different behaviors during stress relaxation, with alloys in peak-aged condition showing the highest stress drop and plastic strain change. As stress relaxation cycles repeated, the decrease in activity of mobile dislocations led to a decrease in stress drop, and the relationship between grain orientation hardness and lattice strain affected the stress relaxation effect.
MECHANICS OF MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Richard A. Michi, Sumit Bahl, Christopher M. Fancher, Kevin Sisco, Lawrence F. Allard, Ke An, Dunji Yu, Ryan R. Dehoff, Alex Plotkowski, Amit Shyam
Summary: The high-temperature deformation behavior of an additively manufactured Al-Cu-Mn-Zr alloy is investigated through ex-situ and in-situ neutron diffraction creep experiments at 300 degrees C. The dominant reinforcement phase in the alloy, theta-Al2Cu, does not contribute to load transfer strengthening during creep deformation. Instead, a load shuffling mechanism is observed where the initial load is transferred from precipitate-free zones to precipitate-strengthened grain interiors. Despite lacking load transfer strengthening, the as-fabricated AM Al-Cu-Mn-Zr alloy shows improved creep resistance compared to a cast alloy with similar composition. The proposed load shuffling mechanism explains the absence of L1(2)-Al3Zr strengthening at 300 degrees C and suggests strategies for enhancing the elevated-temperature mechanical response of AM Al alloys.
Article
Engineering, Biomedical
Yaping Zhang, Yuanding Huang, Frank Feyerabend, Carsten Blawert, Weimin Gan, Emad Maawad, Sihang You, Sarkis Gavras, Nico Scharnagl, Julia Bode, Carla Vogt, Daniela Zander, Regine Willumeit-Roemer, Karl Ulrich Kainer, Norbert Hort
Summary: The presence of intermetallic particles in Mg-Nd alloys has two conflicting effects on corrosion: enhancing micro-galvanic corrosion (negative role) and promoting the formation of a continuous and compact corrosion layer (positive role). As the immersion proceeds, the positive role of intermetallic particles becomes more pronounced, ultimately impacting the corrosion rate of the alloys.
ACTA BIOMATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
C. Ha, J. Bohlen, X. Zhou, H-G Brokmeier, K. U. Kainer, N. Schell, D. Letzig, S. Yi
Summary: This study investigated the differences in texture development and active deformation mechanisms during sheet rolling for binary Mg-RE or Mg-Ca alloys compared to their ternary counterparts with Zn. The analyses were based on in-situ synchrotron experiments and electron backscatter diffraction measurements, revealing direct experimental evidence of texture development and active deformation mechanisms. Higher activations of nonbasal a c+a 1010 a a c+a a slip in the Zn-containing ternary alloys were confirmed through EBSD misorientation analysis.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Sihang You, Yuanding Huang, Hajo Dieringa, Emad Maawad, Weimin Gan, Yaping Zhang, Karl Ulrich Kainer, Regine Willumeit-Roemer, Norbert Hort
Summary: The addition of rare earth element Y can effectively improve the creep properties of magnesium alloys, enhancing both ambient strength and high temperature strength. Y additions exhibit a linear relationship with the yield strength of Mg-Y alloys at room temperature, but reduce the yield strength at high temperatures. These alloys also demonstrate high thermal stability above 200 degrees C. The creep resistance of magnesium is largely improved with small amounts of Y, but further increasing Y content weakens its contribution to creep resistance.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Yaping Zhang, Yuanding Huang, Xiang Chen, Berengere Luthringer-Feyerabend, Ju Xue, Daniela Zander, Regine Willumeit-Roemer, Karl Ulrich Kainer, Norbert Hort
Summary: This study investigates the biodegradation properties of pure magnesium with different iron contents and surprisingly finds that the iron impurity does not have a negative effect on the degradation of pure magnesium, even when the iron content exceeds the previous tolerance limit. Detailed microstructural analyses reveal that the severe local micro-galvanic corrosion caused by the iron impurity promotes the formation of a compact calcium-rich corrosion product layer, protecting the adjacent magnesium matrix from further corrosion.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Petra Maier, Daniel Ginesta, Benjamin Clausius, Norbert Hort
Summary: This study focuses on DieMag633, a cast Mg-Al-Ba-Ca alloy. Brittle interdendritic phases strongly affect crack initiation and propagation under quasi-static and fatigue loading. The material has low failure resistance under tensile loading. Selected fatigue loading sequences were used to investigate crack propagation. DieMag633 in this study contains significant shrinkage cavities and pores that have irregular distribution. The cracking is mainly influenced by Ba- and Ca-rich phases, rather than the Mg-matrix. Transgranular cracking is observed mainly in the compact Ba-rich phase and the lamellar Ca-rich phase.
Article
Materials Science, Multidisciplinary
Abdallah Elsayed, Francesco D'Elia, Comondore Ravindran, Dimitry Sediako
Summary: This research used in-situ neutron diffraction to examine the effect of grain refinement on grain growth during solidification of Al-5 wt.% Cu and Mg-5 wt.% Zn alloys. The findings showed that the addition of grain refiners significantly reduced grain size and affected the microstructure of the alloys. Additionally, quantification of solid fraction growth revealed that grain-refined alloys exhibited a more gradual solid fraction increase.
Article
Nanoscience & Nanotechnology
Shaoyuan Lyu, Guodong Li, Ruixiao Zheng, Wenlong Xiao, Yuanding Huang, Norbert Hort, Minfang Chen, Chaoli Ma
Summary: In this study, an ultrafine-grained Mg-RE alloy was successfully fabricated by simple hot extrusion, and the roles of nano-precipitates and alloying elements in inhibiting the growth of recrystallized grains were investigated. The results suggest that high tension-compression symmetry in Mg alloys can be achieved through grain refinement and texture randomization.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Jiangfeng Song, Hua Zhao, Jinge Liao, Bin Jiang, Ang Zhang, Yuanding Huang, Karl Ulrich Kainer, Norbert Hort, Fusheng Pan
Summary: This study investigated the hot tearing mechanism of Mg-1Al, Mg-0.9Y, Mg-2Gd, Mg-1.5Zn, and Mg-0.5Ca binary alloys by conducting hot tearing tests and utilizing 3D X-ray tomography technology. The results revealed the susceptibility of these alloys to hot tearing and the factors contributing to it, such as temperature range and residual liquid fraction. The discussion also considered factors like fluidity, thermal expansion coefficient, and mechanical property to provide a comprehensive understanding of the hot tearing mechanism.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Yiyi Lu, Yuanding Huang, Julia Bode, Carla Vogt, Regine Willumeit-Romer, Karl Ulrich Kainer, Norbert Hort
Summary: The influences of Gd additions and T4 treatment on the mechanical properties and corrosion of Mg-Gd alloys were investigated. Gd solid solution and intermetallic particles were found to improve the hardness and strength of the alloy, while increasing Gd additions led to higher corrosion rates. T4 heat treatment effectively reduced degradation rates and susceptibility to pitting. Mg-2Gd alloy showed a favorable combination of mechanical properties and low homogeneous degradation rate, making it a potential candidate for implants.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Crystallography
Maria Nienaber, Gerrit Kurz, Dietmar Letzig, Karl Ulrich Kainer, Jan Bohlen
Summary: The application of magnesium flat products is affected by the limited formability at room temperature and the anisotropy of the mechanical properties, which is mainly caused by the underlying hexagonal crystal structure of magnesium and the development of strong crystallographic textures during massive forming processes. This study focuses on the influence of the manufacturing process on the microstructure and texture evolution of flat products made of conventional magnesium alloy AZ31, and discusses the effects on mechanical properties and formability.
Article
Metallurgy & Metallurgical Engineering
Mariano Casas-Luna, Edgar B. Montufar, Norbert Hort, Sebastian Diaz-de-la-Torre, Jose Claudio Mendez-Garcia, Lucie Vistejnova, Adam Brinek, Ales Danhel, Karel Dvorak, Jozef Kaiser, Ladislav Celko
Summary: This study explores the combination of ceramic additive manufacturing and liquid metal infiltration for the production of degradable interpenetrating phase magnesium/hydroxyapatite (Mg/HA) composites. By using material extrusion additive manufacturing and an advanced liquid infiltration method, HA preforms with controlled pore networks were successfully infiltrated with pure Mg and Mg alloys. The pure Mg-based composites exhibited higher compressive yield strength compared to pure Mg, while the Mg alloy-based composites showed similar mechanical properties to other Mg/HA composites. Additionally, the composites demonstrated a faster degradation rate under simulated body conditions.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Review
Metallurgy & Metallurgical Engineering
Hui Shi, Yuanding Huang, Qun Luo, Sarkis Gavras, Regine Willumeit-Roemer, Norbert Hort
Summary: This article provides a brief overview of the diffusion behavior of Mg alloys and discusses the methods for detecting and extracting diffusion coefficients. It reviews the diffusion data of Mg alloys and highlights their significance in designing and applying these alloys.
JOURNAL OF MAGNESIUM AND ALLOYS
(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)
Proceedings Paper
Engineering, Mechanical
Xun Zeng, Dietmar Letzig, Karl Ulrich Kainer, Dikai Guan, Sangbong Yi
Summary: In this study, the influence of Zn or Al addition as a third alloying element on the deformation mechanisms of Mg-Nd-based alloys was investigated. The ZN12 alloy showed lower yield strength and higher fracture strain compared to the AN12 alloy. Slip traces were formed at the early deformation stage in the ZN12 sample, while only a few grains in the AN12 sample showed obvious slip traces. Basal and non-basal slip were preferred in the ZN12 sample compared to the AN12 sample. Both samples exhibited high activity of tensile twinning, but the activation of twins occurred earlier in the ZN12 sample.
MAGNESIUM TECHNOLOGY 2022
(2022)
Article
Engineering, Manufacturing
Felix Benn, Francesco D'Elia, Kerstin van Gaalen, Muzi Li, Savko Malinov, Alexander Kopp
ADDITIVE MANUFACTURING LETTERS
(2022)
