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Characterisation of aluminium alloys by X-ray diffraction line profile analysis

机译：X射线衍射线轮廓分析法表征铝合金

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摘要

From a research and development perspective Alcan Inc. maintains a global leadership position in aluminium can stock by understanding the relationships between processing microstructure and properties. TEM analysis is of little use in examining the associated microstructures from its most important products. In contrast X-ray Diffraction Line Profile Analysis (LPA) has shown that information about the microstructure of heavily cold worked materials may be reliably obtained.;Al-2.5%Mg, Al-4%Cu and Al-0.2%Cu-1.2%Mg based alloys were processed to provide microstructures modified by 'deformation only', 'precipitation only' and 'precipitation and deformation' respectively. The processing routes from these alloys were optimised for reproducibility of X-ray diffraction results. This involved stages of alloy development that included 0.4% iron additions and sophisticated thermomechanical processing routes.;A systematic approach to LPA was made and X-ray diffraction mounting techniques, profile fitting and Kai stripping were optimised to obtain robust and reproducible results using a conventional X-ray diffractometer.;A number of LPA techniques were investigated and reliable measurements of crystallite size and (square) root mean squared sfrains (r.m.s.s.) were obtained by applying the Warren-Averbach LPA technique. By adapting and developing models the results from LPA were used to estimate dislocation densities and precipitation effects. To help in interpreting the LPA results, TEM was used as a complementary technique.;The major conclusions of the project were: (i) Routine methods for LPA using as rolled sheet may be implemented at Alcan Inc.'s Banbury Laboratories. This would allow for the determination of crystallite size, r.m.s.s., dislocation densities and coherent precipitate effects. (ii) In cold worked structures the crystallite size was related to the spacing of dislocations, while in a recovered material it was related to the subgrain size. At high levels of cold work, dislocation rearrangement occurred to lower the energy in the lattice that reduced the trend of decreasing crystallite size with cold work. The crystallite size in Al-Cu alloys was related to the spacing of parallel precipitates. (iii) LPA may be used to distinguish between cold worked and recovered structures in an Al-Mg alloy. This was possible because cold worked and recovered structures have different dislocation arrangements that lead to variations in the shape of diffraction peaks. (iv) An estimation of Vickers Hardness Number and yield strength may be calculated directly from LPA in conjunction with a model and calibration curve. (v) S' (Al2CuMg) did not contribute to X-ray Line Broadening. Therefore LPA may be performed on S' containing materials to investigate effects caused by other sources of broadening. (vi) The project has had a positive financial impact on Alcan's research and development activities. The project also contributes towards the incorporations technological competitive advantage.
机译：从研究和开发的角度来看，加拿大铝业公司通过了解加工微观结构和性能之间的关系，在铝罐库存方面保持全球领先地位。 TEM分析在从其最重要的产品检查相关的微观结构方面几乎没有用。相比之下，X射线衍射线轮廓分析（LPA）显示，可以可靠地获得有关冷加工材料的微观结构的信息。Al-2.5％Mg，Al-4％Cu和Al-0.2％Cu-1.2％对镁基合金进行加工，以提供分别通过“仅变形”，“仅沉淀”和“沉淀和变形”改性的微观结构。优化了这些合金的加工路线，以提高X射线衍射结果的可重复性。这涉及合金的开发阶段，其中包括添加0.4％的铁和复杂的热机械加工路线。；采用了LPA的系统方法，并使用常规方法优化了X射线衍射安装技术，轮廓拟合和Kai剥离，以得到可靠且可重复的结果X射线衍射仪。研究了许多LPA技术，并通过使用Warren-Averbach LPA技术获得了晶粒尺寸和（均方根）平方根均方根（rmss）的可靠测量值。通过改编和发展模型，LPA的结果被用于估算位错密度和降水效应。为了帮助解释LPA结果，将TEM用作辅助技术。该项目的主要结论是：（i）Alcan Inc.的Banbury Laboratories可以使用卷材作为LPA的常规方法。这将允许确定微晶尺寸，r.m.s.s。，位错密度和相干沉淀作用。 （ii）在冷加工结构中，微晶尺寸与位错间距有关，而在回收材料中，其微晶尺寸与亚晶粒尺寸有关。在高水平的冷作中，发生位错重排以降低晶格中的能量，这降低了冷作时晶粒尺寸减小的趋势。 Al-Cu合金的微晶尺寸与平行析出物的间距有关。 （iii）LPA可用于区分Al-Mg合金中的冷加工组织和回收组织。这是可能的，因为冷加工和回收的结构具有不同的位错排列，从而导致衍射峰的形状发生变化。 （iv）维氏硬度数和屈服强度的估算可以直接从LPA结合模型和校准曲线来计算。 （v）S'（Al2CuMg）对X射线线展宽没有贡献。因此，可以在含S'的材料上进行LPA，以研究由其他扩展来源引起的影响。 （vi）该项目对加铝的研发活动产生了积极的财务影响。该项目还有助于公司的技术竞争优势。

著录项

  • 作者

    Akram, Naeem J.;

  • 作者单位

    The University of Manchester (United Kingdom).;

  • 授予单位 The University of Manchester (United Kingdom).;
  • 学科 Materials science.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 249 p.
  • 总页数 249
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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