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Platform Science and Technology for Advanced Magnesium Alloys -Extra Light Metals in the 21st Century-

先进镁合金平台科学与技术-21世纪的超轻金属-

基本信息

批准号：
11225101
负责人：
KOJIMA Yo
金额：
$ 45.76万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11225101/
关键词：
Magnesium Alloys Microstructure and Structure Control Surface and Interface Control Recycle Optimum Design for Lightening Semi-Solid Forming Process New Functionality Surface Modification プロチウム吸蔵合金

项目摘要

In the current four-year term project, new platform science and technology is proposed as a core concept of research and development of advanced magnesium alloys together with understanding of their intrinsic characteristics. The research fields related to advanced super-light magnesium alloys for 21st Century have been focused to the selected three categories ; ( 1)Search for new premium alloys and a structural design from the view points of microstructure control, (2)Establishment of environmental-friendly surface modification and recycling for the ecomaterials desing and green processing, and (3)High performance design and processing in functionality. Each research group is introduced together with its strategic directions toward future R & D for advanced magnesium alloys and has its own joint research network to drive new research directions.Typical results are summarized as follows ; a nanocrystalline Mg-1mol%Zn-2mol%Y bulk alloy sample prepared by warm extrusion of rapidly solidi … More fied powders is composed of grains of about 50-200 nm in diameter, which are divided into two types; hcp-Mg solid solution grain and fine-lamellar grains consisting of a novel long-period ordered structure with hexagonal lattice of 6H-type (ABCBCB)., resulting in high 0.2% proof strength of about 610 MPa and sufficient elongation of about 5% at room temperature. Dislocation cross slip from basal plane to non-basal planes, dynamic recovery within twins and in untwined matrix, and grain boundary sliding are found to occur in whole grains of the magnesium alloy specimens with fine-grains of lower than 10μm even at room temperature. AZ61 alloy specimen indicates high strength of 350MPa and high ductility of 33% by the refinement of grains and precipitates caused by dynamic recrystallization and dynamic precipitation during severe warm working. To be free from the classical theory, materials design on the basis of the first principle molecular dynamics calculation is proposed for new high creep resistant magnesium alloys. A protective high purity coating applying magnesium vapor deposition technique, polymer plating of triazine dithiols easily peeled at the cryogenic temperature or decomposed by brittle fracture, and their solid state recycling technology are developed as environmentally benign surface modification without chromium. The co-electrodeposition of rare earth metals (RE) with Mg in the molten salt system including RE chlorides is found to be available for the production of Mg-RE alloys. Also, semi-solid continuous casting process is established for the fabrication of fine-and globular-grained billet and adequate magnesium alloys is developed for high speed semi-solid processing at lower temperatures as a near net complex shape forming process. As a new route to fabricate the functional magnesium alloys, bulk mechanical alloying process as a solid state synthesis was proposed to successfully synthesize the magnesium base hydrogen absorbing alloys and thermoelectric semiconductor in the solid state with fine structure and accurate chemical composition. This bulk mechanical alloying also provides us non-equilibration to make solid state synthesis. Furthermore, ternary or quaternary magnesium base alloy bulk can be directly fabricated to have the same chemical composition as predicted in design at extremely lower temperature than the melting temperatures of constitutive elements. On this fundamental knowledge, the solid-state recycling is proposed to fabricate the reinforced magnesium alloy composite parts and performs with in-situ precipitated Mg_2Si and MgO in fine and uniform.On the basis of the obtained results, platform science and technology for environmentally benign and high performance magnesium alloys is constructed as an industrial base material for the next generation. Less

在本四年期项目中，提出了新平台科学和技术作为先进镁合金研究和开发的核心概念，并了解其内在特性。21世纪先进超轻镁合金的研究领域主要集中在以下三个方面：（1）从微观结构控制的角度寻找新型优质合金和结构设计;（2）为环境材料设计和绿色加工建立环境友好的表面改性和回收利用;（3）功能性高性能设计和加工。介绍了各研究组在未来先进镁合金研发方面的战略方向，并介绍了各自的联合研究网络，以推动新的研究方向。典型的研究结果如下：采用快速凝固的温挤压法制备了纳米晶Mg-1mol%Zn-2mol%Y块体合金样品， ...更多信息烧结粉末由直径约50-200 nm的晶粒组成，这些晶粒分为两种类型：hcp-Mg固溶体晶粒和由具有6 H型六方晶格的新型长周期有序结构（ABCBCB）组成的细片层晶粒。导致约610 MPa的高0.2%保证强度和在室温下约5%的足够伸长率。结果表明，即使在室温条件下，晶粒尺寸小于10μm的镁合金试样也存在位错从基面向非基面的错动、孪晶内和非孪晶基体内的动态回复以及晶界滑移。AZ 61镁合金在剧烈温加工过程中，通过动态再结晶和动态析出，细化了晶粒和析出相，使AZ 61镁合金具有350 MPa的高强度和33%的高塑性。为了摆脱经典理论的束缚，提出了基于第一性原理分子动力学计算的新型高抗蠕变镁合金材料设计方法。采用镁气相沉积技术制备的高纯度保护涂层、低温易剥落或易脆裂的三嗪二硫醇类聚合物镀层及其固态回收技术，是一种环境友好的无铬表面改性技术。研究了在含稀土氯化物的熔盐体系中稀土与镁共电沉积制备镁-稀土合金的可行性。此外，半固态连续铸造工艺被建立用于制造细晶粒和球形晶粒的坯料，并且适当的镁合金被开发用于在较低温度下的高速半固态加工作为近净复杂形状成形工艺。作为制备功能镁合金的一种新途径，本文提出了一种固相合成的机械合金化方法，成功地在固态下合成了具有精细结构和精确化学成分的镁基储氢合金和热电半导体材料。这种本体机械合金化也为我们提供了非平衡来进行固态合成。此外，三元或四元镁基合金块体可以在比构成元素的熔化温度极低的温度下直接制造成具有与设计中预测的相同的化学组成。在此基础上，提出了利用固相再生技术制备增强镁合金复合材料零件，并原位析出细小均匀的Mg_2Si和MgO，构建环境友好型高性能镁合金的科学技术平台，作为下一代工业基础材料。少