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Application of the Mechanical Alloying Technique to the Construction of Low-temperature Phase Diagrams

机械合金化技术在低温相图构建中的应用

基本信息

批准号：
06650724
负责人：
KOYANO Tamotsu
金额：
$ 1.28万
依托单位：
University of Tsukuba (1995)Nagoya University (1994)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650724/
关键词：
Mechanical Alloying Phase Diagrams Fe-Cr sigma-phase メカニカルアロイレグ σ相

项目摘要

A technique, so called mechanical alloying, has attracted much attention as a new method to produce metastable materials through not only the solid-solid but also solid-gas reactions. Powders subjected to ball milling are heavily cold worked and energized to form metastable phases. The energy accumulated during ball milling is believed to be stored in the grain boundaries and lattice defects. These lattice imperfections would play a role in accelerating atomic diffusion upon annealing of ball milled powders, even at low temperatures, where atomic diffusion no longer effectively proceeds in ordinary bulk samples. The aim of present research is to investigate the applicability of the mechanical alloying technique (hereafter abbreviated as MA) to the sample preparation for the determination of the phase diagrams in that temperature range. The major sesults obtained are summarized below :1) The phase transformations occurring in the MA sample were found to proceed at a several order higher … More rate as compared to that in bulk samples. This offers us an opportunity to shed some light on the determination of equilibrium phase diagrams at relatively low temperature regions.2) This rapid reaction is found to be attributed to the small grain size and the accumulation of the lattice strain.3) The MA provides an opportunity to produce a large amount of the sample in single phase much easier than the DC sputtering method.4) Precise control of the milling condition results in reducing the impurities coming from a ballmill vial, balls and the ambient gas.5) The sigma* (Cr) + (alpha-Fe) eutectoid temperature in the Fe-Cr system is lower than 480ﾟC.The two-phase separation occurring this system proceeds much faster than the formation of the sigma phase. In other words, the sigma-phase is formed after the completion of the two-phase separation.6) The alpha-phase is obtained by MA in the Fe-V and Fe-Cr systems starting from both a mixture of the respective elemental metal powders and the sigma-phase powders.7) We have determined, for the first time, the Curie temperature in a composition range 34<X<53 in the Fe_<100-X>V_X system.8) A guide line was established to trace the MA process for a combination fo ferromagnetic and nonferromagnetic elements by means of magnetic measurements. Less

机械合金化技术作为一种既能通过固-固反应又能通过固-气反应制备亚稳态材料的新方法，引起了人们的广泛关注。经受球磨的粉末被严重冷加工并通电以形成亚稳相。球磨过程中积累的能量被认为储存在晶界和晶格缺陷中。这些晶格缺陷将在加速球磨粉末退火后的原子扩散中发挥作用，即使在低温下，其中原子扩散在普通块状样品中不再有效地进行。本研究的目的是调查的机械合金化技术（以下简称MA）的样品制备在该温度范围内的相图的测定的适用性。主要结果如下：1）MA样品中的相变是在高几个数量级上进行的 ...更多信息与散装样品相比，这为我们提供了一个在相对较低温度区域确定平衡相图的机会。2）发现这种快速反应归因于小晶粒尺寸和晶格应变的积累。3）MA提供了一个比DC溅射方法更容易产生大量单相样品的机会。4）研磨条件的精确控制导致减少来自球磨机小瓶的杂质，5）西格玛 *（Cr）+在Fe-Cr系中，（α-Fe）共析温度低于480 ℃。该体系发生的相分离比σ相的形成进行得快得多。6）在Fe-V和Fe-Cr系中，从各自的元素金属粉末和σ相粉末的混合物开始，通过MA获得α相。7）我们首次测定了Fe_ V_X系中34<X<53组成范围内的居里温度<100-X>。8）建立了一条用磁性测量方法跟踪铁磁和非铁磁元素组合的MA过程的指导线。少