Exploiting Magnesium Alloys Containing Long-Period Stacking Order (LPSO) Phases

开发含有长周期堆叠顺序 (LPSO) 相的镁合金

• 批准号: 1830571
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1830571
• 关键词: Exploiting; Magnesium; Alloys; Containing; Long

The recent discovery of the excellent properties that can be obtained using magnesium alloys that contain long period stacking ordered (LPSO) phases has led to intense research interest in these materials over the last decade. However, most of the studies to date have been concerned with the structure of these materials on the nano-scale, or on producing the maximum value in a single property (e.g. strength) without consideration of the process limitations or property requirement balance needed in a practical alloy.The present PhD will address the scientific issues required to exploit LPSO containing magnesium alloys as practical materials for industrial application. The first step (year 1) will be to understand how the current LPSO containing commercial alloys achieve their favourable combination of good strength, ductility, and isotropy through a consideration of the microstructure and texture developed during extrusion and heat treatment. The role of primary LPSO phase vs. secondary (precipitated) LPSO will be studied. Texture evolution in the LPSO and matrix will be distinguished by developing an EBSD technique to separate these contributions. The mechanical break up of the primary LPSO phase and its subsequent redistribution during extrusion will also be investigated. Where necessary, the experimental work will be complemented by finite element modelling (including crystal plasticity) to predict how the size, fraction, and distribution of the LPSO and matrix phases influence the overall alloy properties (and property anisotropy).The next steps (years 2 and 3) will be to use the understanding gained from year 1 to develop LPSO alloys for practical use with an optimized property balance. Factors such as optimum fraction and selection of LPSO phase (by utilization of different LPSO forming elements), grain refinement, precipitation of secondary LPSO, and texture control will be considered. Modelling will be used to design microstructures capable of being tuned to particular property goals (e.g. maximum strength, minimum anisotropy etc.) The alloy optimization strategies will be tested be producing and evaluating material using both microscopy and mechanical testing.

最近发现，可以使用含有长周期堆叠有序（LPSO）相的镁合金获得优异的性能，这在过去十年中引起了对这些材料的强烈研究兴趣。然而，迄今为止，大多数研究都关注这些材料在纳米尺度上的结构，或者在单一性能（例如强度）中产生最大值，而不考虑实际合金中所需的工艺限制或性能要求平衡。本博士将解决开发含镁合金的LPSO作为工业应用的实际材料所需的科学问题。第一步（第1年）将是了解目前含LPSO的商业合金如何通过考虑挤压和热处理过程中形成的微观结构和织构来实现其良好强度、延展性和各向同性的有利组合。将研究初级LPSO相与次级（沉淀）LPSO的作用。纹理演变的LPSO和矩阵将区分开发EBSD技术，以分离这些贡献。还将研究在挤出过程中初级LPSO相的机械破碎及其随后的再分布。在必要的情况下，实验工作将通过有限元建模（包括晶体塑性）来补充，以预测LPSO和基体相的尺寸、分数和分布如何影响整体合金性能（和性能各向异性）。下一步（第2年和第3年）将利用第1年获得的理解，开发具有优化性能平衡的LPSO合金用于实际应用。将考虑诸如LPSO相的最佳分数和选择（通过利用不同的LPSO形成元素）、晶粒细化、二次LPSO的析出和织构控制的因素。建模将用于设计能够调整到特定属性目标（例如最大强度，最小各向异性等）的微结构。合金优化策略将通过使用显微镜和机械测试生产和评估材料进行测试。