Effect of shear strain on metal deformation and microstructural evolution

该项目的目的是实现金属的单一剪切变形(即无轴向应变成分)，并确定剪切应变对变形机制、微观结构和织构演变的影响，并开发新的加工工艺，以适应各种结构应用的金属材料的微观结构和织构。这项研究将利用斯旺西最先进的显微镜和COE力学测试设备、中央中子衍射设施(ISIS，Didcot)和晶体塑性有限元模拟(CPfem)来发展对力学的理解。方法：由于具有非常不同的晶体结构，钛、锆和镁(HCP)、铝(FCC)和Nb具有工业相关性，因此被选为本研究的对象。这项研究的开始将专注于实现与COE加载机兼容的凹槽压力机来执行鞋底剪切变形。为了从机理上了解，将使用斯旺西提供的光学、扫描电子显微镜、电子显微镜和EBSD等一系列显微镜设备对变形和再结晶不同阶段的样品进行分析。在ISIS的Engin-X的现场研究将提供不同粒子族的典型晶格应变演化的细节，并允许深入了解不同变形模式的活动。这些量也可以作为CPFE的输入，以便更好地了解变形机制。CPFE还将被用于预测织构和晶格应变的演化。

The aim of this project is to perform sole shear deformation (i.e., without axial strain components) of metals and determine the effect of shear strain on deformation mechanisms, microstructure and texture evolution and develop novel processing procedures to tailor the microstructure and texture of metallic materials for various structural applications. This research will exploit state of the art advanced microscopy and CoE mechanical testing units in Swansea, the central neutron diffraction facility (ISIS, Didcot) and Crystal plasticity finite element modelling (CPFEM) to develop a mechanistic understanding.Methodology: The metals having very different crystal structures, Ti, Zr and Mg (hcp), Al (fcc) and Nb are selected for this research due to their industrial relevance. The start of this research will focus on implementing a Groove Press compatible with the CoE loading machines to perform sole shear deformation. For a mechanistic understanding, specimens from different stages of deformation and recrystallization will be analysed using a range of microscopy facilities, optical, SEM, TEM and EBSD, available in Swansea. In-situ studies at Engin-X, ISIS, will provide details of representative lattice strain evolution of different grain families and allows insights into the activity of different deformation modes. These quantities can also be inputs for CPFEM for better understanding of the deformation mechanisms. CPFEM will also be employed to predict texture and lattice strain evolution.