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Embryo-to-lamella transition of grain boundary twins in magnesium

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Journal of Magnesium and alloys 2023年第12期11卷 4485-4497页

作者： Mariyappan Arul Kumar Irene J Beyerlein Materials Science and Technology division Los Alamos National LaboratoryLos AlamosNM 87545USA Mechanical Engineering Department Materials DepartmentUniversity of CaliforniaSanta BarbaraCA 93106USA

A combined experimental and computational analysis is performed to investigate the less commonly studied embryo-to-lamella transition of deformation twins in magnesium. This work aims to understand the structural variables controlling the embryo-to-lamella transition from grain boundaries. Statistical analysis of hundreds of early-stage twins in the lightly deformed microstructure reveals a prevailing wedge shape,with a much thicker base along the grain boundary(GB) where they originate and a thinner tip terminating in the crystal. The analysis also shows that the GB base is super thick and identifies a minimum GB twin thickness among all early-stage twins that is about one micron. A crystal plasticity-based full-field model is employed to calculate the driving forces to migrate the boundary of a three-dimensional GB twin embryo. The stress analysis, considering a full range of embryo shapes and neighboring grain orientations, indicate that the twin embryo is most likely going to form a wedge shape when it first propagates. The calculations predict that the thickness of the embryo at the GB needs to be significantly larger than its length into the crystal in order to propagate into the crystal. The analysis finds that the more aligned the twin embryo variant is with basal slip in the neighboring grain, the thinner the twin embryo needed for propagation.

关键词： Magnesium Twin embryo Crystal plasticity Nucleation Grain neighbor

Effects of solution heat treatment on corrosion resistance of 5083F Al alloy

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中国有色金属学会会刊：英文版 2009年第4期19卷 887-891页

作者： Seong-Jong KIM Seok-Ki JANG division of Marine Engineering Mokpo Maritime University

Aluminum alloys are used as substitutes for fiber reinforced polymer(FRP) in ships and ***,ships constructed with 5000-series Al alloy suffer a little corrosion in the marine environment,when they run in high speed,and high flow rate,***,solution heat treatment was carried out to prevent *** optimal heat treatment involved heating specimens for 120 min at 420 ℃ and then cooling them in *** addition,the optimal ageing condition involved ageing specimens for 240 min at 180 ℃.The slow strain rate test(SSRT) in a seawater revealed that heat treatment under optimal conditions produced improved elongation,time-to-fracture and amount of dimples compared with the as-received specimen.

关键词：铝合金腐蚀性固溶处理热处理生产纤维增强聚合物电阻慢应变速率海洋环境

Biocompatibility of Mg-Nd-Zn-Zr alloy with rabbit blood

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Chinese Science Bulletin 2013年第23期58卷 2903-2908页

作者： WANG YongPing OUYANG YuanMing HE YaoHua CHEN DaoYun JIANG Yao MAO Lin NIU JiaLin ZHANG Jian YUAN GuangYin Department of Orthopaedics First Hospital of Lanzhou University Department of Orthopaedics Sixth People's Hospital of Shanghai Jiao Tong University National Engineering Research Center of Light alloys Net Forming School of Materials Science and Engineering Shanghai Jiao Tong University

In this study, in vitro blood biocompatibility of Mg-Nd-Zn-Zr (JDBM) alloy was investigated to determine its suitability as a degradable medical biomaterial. Blood biocompatibility was assessed by blood cell aggregation, platelet adhesion, and protein adsorption. A titanium alloy was used as control. The results showed that the JDBM alloy did not induce significant blood cell aggregation, platelet adhesion, and protein adsorption comparison with the titanium alloy (P>0.05). Our data indicate that the JDBM alloy has excellent in vitro blood compatibility, and thus can be considered as a potential degradable biomaterial for medical applications with respect to hemocompatibility.

关键词：生物相容性钛合金血液相容性血小板粘附蛋白质吸附钕镁生物材料

Deformation heterogeneity of Ti under cryogenic channel-die compression

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Progress in Natural Science:Materials International 2011年第4期21卷 277-285页

作者： K.H.KIM S.K.HWANG division of Materials Science and Engineering Inha University

Commercial purity Ti was subjected to channel die compression in liquid nitrogen for the purpose of studying its deformation characteristics from the viewpoint of the grain refinement induced by severe plastic *** specimens showed microstructural heterogeneity in that the initial blocky grains of about 50 urn in size turned into a mixture of the easily deforming soft grains and the hard grains revealing local concentration of dislocations and deformation *** electron back scattered diffraction analysis the in-grain misorientation-axis distribution was studied,from which it was found that the deformation heterogeneity resulted from the anisotropy of individual grains with respect to the compression die:while the soft grains were those oriented favorably for the prismslip,the hard ones were oriented for non-prism slips and deformation *** difference in the response of individual grains,therefore,led to a remarkable effect of the crystal texture of specimens on the maximum strain that can be imposed on specimens without *** on the present results,a way to achieve expedient grain refinement through the cryogenic plane-strain compression was suggested.

关键词： titanium cryogenic deformation texture microstructure

Material Characterization of Ni Base Alloy for Very High Temperature Reactor

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Journal of Materials Science & Technology 2013年第12期29卷 1184-1190页

作者： Dong-Jin Kim Gyeong-Geun Lee Dae Jong Kim Su Jin Jeong Nuclear Materials division Korea Atomic Energy Research Institute

The generation of highly efficient electricity and the production of massive hydrogen are possible using a very high temperature reactor （VHTR） among generation IV nuclear power plants. The structural material for an intermediate heat exchanger （IHX） among numerous components should be endurable at high temperature of up to 950 °C during long-term operation. Impurities inevitably introduced in helium as a coolant facilitate the material degradation by corrosion at high temperature. In the present work, the surface reactions available under controlled impure helium at 950 °C were investigated based on the thermodynamics and the corrosion tests were performed in a temperature range of 850-950 °C during 10-250 h for commercial Alloy 617 as a candidate material for an IHX. Moreover, the mechanical property and microstructure for nickel-based alloys fabricated in laboratory were evaluated as a function of the processing parameters such as hot rolling and heat treatment conditions. From the reaction rate constant obtained from an impure helium control system for a material evaluation, it was predicted that the outer oxide layer thickness, internal oxide depth, and carbide- depleted zone depth reach about 116, 600 and 1000 μm, respectively when Alloy 617 is exposed to an impure helium environment at 950 ~C for 20 years. For Ni-Cr-Co-Mo alloy, subsequent annealing and a combination of cold working and subsequent annealing following solution annealing caused increases in the grain boundary carbide coverage and size. The angular distribution of the grain boundary as well as the carbide distribution was also changed leading to a consequent improvement of the mechanical property at 950 °C in air.

关键词： Nickel base alloy Intermediate heat exchanger High temperature reactor Corrosion Mechanical property

Improving hydroxyapatite coating ability on biodegradable metal through laser-induced hydrothermal coating in liquid precursor:Application in orthopedic implants

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Bioactive Materials 2023年第7期25卷 796-806页

作者： Jaeho Park Seung-Hoon Um Youngmin Seo Jaehong Lee Yu-Chan Kim Myoung-Ryul Ok Suk-Won Hwang Jeong-Yun Sun Hyung-Seop Han Hojeong Jeon Biomaterials Research Center Biomedical Research DivisionKorea Institute of Science and Technology(KIST)Seoul02792South Korea Department of Materials Science and Engineering Seoul National University(SNU)Seoul08826South Korea division of Biomedical Science and Technology KIST SchoolKorea University of Science and TechnologySeoul02792South Korea KU-KIST Graduate School of Converging Science and Technology Korea UniversitySeoul02841South Korea

During the past decade,there has been extensive research toward the possibility of exploring magnesium and its alloys as biocompatible and biodegradable materials for implantable *** practical medical application,however,has been limited to specific areas owing to rapid corrosion in the initial stage and the consequent *** coatings can significantly reduce the initial corrosion of Mg alloys,and several studies have been carried out to improve the adhesion strength of the coating to the surfaces of the *** composition of hydroxyapatite(HAp)is very similar to that of bone tissue;it is one of the most commonly used coating materials for bone-related implants owing to favorable osseointegration *** this study,HAp was coated on Mg using nanosecond laser coating,combining the advantages of chemical and physical *** heat generated in the liquid precursor by the laser improved the adhesion of the coating through the precipitation and growth of HAp at the localized nanosecond laser focal area and increased the corrosion resistance and cell adhesion of *** physical,crystallographic,and chemical bondings were analyzed to explore the mechanism through which the surface adhesion between Mg and the HAp coating layer *** applicability of the coating to Mg screws used for clinical devices and improvement in its corrosion property were *** liquid environment-based laser surface coating technique offers a simple and quick process that does not require any chemical ligands,and therefore,overcomes a potential obstacle in its clinical use.

关键词： Biodegradable metal HAp coating Nanosecond laser Photothermal synthesis Soret effect(thermophoresis)

THE SYNTHETIC PROCESS OF TiNi WITH FACE-CENTRED CUBIC LATTICE SYSTEM

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Chinese Science Bulletin 1986年第10期31卷 671-673页

作者：顾菡珍周宇 Deportment of Chemistry Peking University Deportment of Chemistry Peking UniversityiFe in the hydrogen storage materialof Titanium system has been studied by many people lately. Inconvenience has been experienced by users of TiFe because high temperature and pressure are needed by the activation process of this alloy. A lot of people have been studying alloys of ternary and quaternary systems based on Ti-Co

TiFe in the hydrogen storage materialof titanium system has been studied by many people lately. Inconvenience has been experienced by users of TiFe because high temperature and pressure are needed by the activation pr... 详细信息

关键词： experienced quaternary FACE gases users resid 别山 passed 树滋园邑

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纯钛和镍包埋渗铝的热力学研究(英文)

中国有色金属学会会刊：英文版 2013年第6期23卷 1838-1846页

作者： H.R.KARIMI ZARCHI M.SOLTANIEH M.R.ABOUTALEBI X.GUO Centre of Excellence for High Strength alloys Technology School of Metallurgy and Materials EngineeringIran University of Science and Technology State Key Laboratory of Solidification Processing Northwestern Polytechnical University

分别在敞开和密闭系统中进行纯钛和纯镍的气相渗铝实验。渗铝实验在1100℃下进行3h,包埋粉末含10%Al、5%NH4Cl和85%Al2O3。在敞开条件下,渗铝后纯钛的表面会生成α(Al)固溶体,样品的质量损失达到32.37%。然而,在密闭条件下,纯钛样品的... 详细信息

分别在敞开和密闭系统中进行纯钛和纯镍的气相渗铝实验。渗铝实验在1100℃下进行3h,包埋粉末含10%Al、5%NH4Cl和85%Al2O3。在敞开条件下,渗铝后纯钛的表面会生成α(Al)固溶体,样品的质量损失达到32.37%。然而,在密闭条件下,纯钛样品的表面生成TiAl3层和α(Al)固溶体,没有质量损失。热力学分析表明,在敞开条件下对纯钛渗铝时,会生成钛的氯化物,导致其质量减少。而在密闭条件下,由于生成的氯化物会达到平衡状态而使生成反应停止。相反,无论是在敞开或密闭条件下,纯镍样品都可以进行表面渗铝,不会导致质量损失。在两种状态下,镍的表面都生成了AlNi和Ni3Al相。

关键词：包埋渗铝反应钛镍热力学气相渗铝

Extrusion limit diagram of AZ91–0.9Ca–0.6Y–0.5MM alloy and effects of extrusion parameters on its microstructure and mechanical properties

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Journal of Magnesium and alloys 2022年第12期10卷 3447-3458页

作者： Dong HeeLee Ye Jin Kim Sang-Hoon Kim Byoung Gi Moon Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Agency for Defense Development Daejeon 34186Republic of Korea Advanced Metals division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

An AZ91–0.9Ca–0.6Y–0.5MM(AZXWMM91100) alloy, which has higher corrosion resistance, ignition resistance, and extrudability than a commercial AZ91 alloy, has been developed recently. In this study, the AZXWMM91100 alloy is extruded at various temperatures(300–400 ℃) and ram speeds(1–14.5 mm/s), and the cracking behaviors, microstructure, and tensile properties of the extruded materials are systematically analyzed. On the basis of the pressure limit and surface and internal cracking limit, the extrusion limit diagram providing a safe extrusion processing zone is established. All of the materials extruded at temperatures and speeds within the safe extrusion processing zone have high surface quality and moderate tensile ductility with an elongation higher than 10%. Moreover, they have a fully recrystallized grain structure and contain undissolved particle stringers arranged parallel to the extrusion direction. The grain size of the extruded material does not show any relationship with the Zener–Hollomon parameter(Z). However, the yield strength(YS) of the extruded material is inversely proportional to the logarithm of the Z value, and their relationship is expressed as YS =-31.2·log(Z) + 536. These findings may broaden the understanding of the AZXWMM91100 alloy with excellent chemical and physical properties and provide valuable information for the development of high-performance extruded Mg products using this alloy.

关键词： Magnesium Extrudability Extrusion limit diagram Microstructure Tensile properties