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Grain Refinement of Al-Mg alloy by Hydrogenation Treatment and Its mechanism Analysis

加氢处理铝镁合金晶粒细化及其机理分析

基本信息

批准号：
12650702
负责人：
FUNAMI Kunio
金额：
$ 2.18万
依托单位：
Chiba Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

The grain refinement is noticed, as method to enhance the strength of materials and to be appeared the superplasticity behavior. The subject of this study has shown that, in 5083AI (AI-Mg) alloy, this microstructure with fine grain size can be achieved by imposing extremely large plastic strains during work processing using characteristic properties such as hydrogen absorption and dehydrogenation at high temperature. Hydride precipitations MgH_2 obtained in this treatment were more useful to develop the high-density dislocation structure in alloy as dislocation pileup sources.The following results of this study were obtained :2001〜20011 : Hydrogenation treatment was carried out in 773K for 14. 4ks and in hydrogen atmosphere under 0. 4MPa. The hydrogenated samples were carried out heavy cold rolling with the 90% reduction ratio An existence of hydrides was determined by an X-ray diffraction analysis and TEM observation using tritium technique An induced hydrogen content was about 107×10 … More ^2 mass%. Then, to obtain the fine grain sized material, heat treatment was performed to do rapid recrystallization in salt bath. The materials were finally heated at 523K in vacuum (0. 1Pa) for dehydrogenation for 30hr. The residual hydrogen content was 0. 9×10^2 mass%. The hydrogenated samples indicates wavy deformation traces to be prevented easy deformation and shows more fine grain structure (2. 5 u m). Yield strength and tensile strength increased more than 1. 5times in comparison with that of non-hydrogenated specimen.2 : An existence of hydrides was determined by an x-ray diffraction analysis and TEM observation using tritium technique. The grain size is finer with induced hydrogen content.2001〜20021 : For superplasticity behavior of hydrogenated specimen, elongation was about 300% at 625K and 5×10^3 s^1 strain rate. The fatigue strength of these samples was 1. 8times higher than that of non-hydrogenated samples. However, in corrosion test, these samples did not indicate remarkable improvement. Less

晶粒细化作为提高材料强度的方法而受到关注并出现超塑性行为。本研究的课题表明，在5083AI（AI-Mg）合金中，利用高温吸氢和脱氢等特性，在加工过程中施加极大的塑性应变，可以实现这种细晶粒的微观结构。该处理中得到的氢化物析出物MgH_2作为位错堆积源更有利于合金中高密度位错结构的形成。本研究得到如下结果：2001〜20011：在773K、14. 4ks、0. 4MPa氢气气氛下进行氢化处理。对氢化样品进行90％压下率的重冷轧。通过X射线衍射分析和使用氚技术的TEM观察来确定氢化物的存在。诱导氢含量约为107×10…更多^2质量％。然后，为了获得细晶粒材料，进行热处理以在盐浴中进行快速再结晶。最后将材料在真空(0.1Pa)下于523K加热脱氢30hr。残留氢含量为0. 9×10^2质量%。氢化样品显示出波状变形痕迹，以防止容易变形，并显示出更细的晶粒结构（2. 5 u m）。与未氢化样品相比，屈服强度和拉伸强度增加超过1. 5倍。2：通过X射线衍射分析和使用氚技术的TEM观察来确定氢化物的存在。随着氢含量的增加，晶粒尺寸变细。2001〜20021：对于氢化样品的超塑性行为，在625K和5×10^3 s^1应变速率下，伸长率约为300％。这些样品的疲劳强度比非氢化样品高1. 8 倍。然而，在腐蚀测试中，这些样品并没有表现出明显的改善。较少的