Fundamental investigation of the mechanisms of deformation and recrystallisation of cold deformable Mg alloys micro-alloyed with are earth elements and microstructure optimization for the development of a new class of Mg-alloys.

具有六方密排晶体结构的传统镁合金在室温下的成形性非常有限，并且具有明显的力学各向异性，这使得它们难以在工业过程中处理。一类似乎克服了这些缺点的镁合金是那些与稀土元素（RE）如Ce或MM（杂金属，稀土元素与主要成分Ce的混合物）的微合金。该材料可进行冷轧，变形程度高，变形程度较弱。稀土元素对冷变形性能和织构演化的影响主要归因于剪切带的强烈形成，但具体机制尚不清楚。在随后的退火处理中，剪切带如何影响组织和织构演变也不清楚。因此，这里提出的项目的目的是对这些合金的变形和再结晶机制进行基础研究。将生产不同合金成分的样品，进行变形和退火。扫描电镜和透射电镜中的高分辨率取向显微镜技术以及FIB-SEM中的三维取向显微镜将应用于表征不同变形和再结晶程度的样品。对变形和再结晶机制的充分理解对于进一步开发这类有前途的材料至关重要。

Conventional magnesium wrought alloys with hexagonal close packed crystal structure suffer from a strongly limited formability at room temperature and a marked mechanical anisotropy which makes them difficult to handle in industrial processes. A class of Mg-alloys that seems to overcome these shortcomings is those micro-alloyed with rare-earth (RE) elements like Ce or MM (misch-metal, a mixture of rare earth elements with major constituent of Ce). The material can be cold rolled to high deformation degrees and the deformation is rather weak. The effects of RE elements on the cold deformability and texture evolution have been ascribed to the intense formation of shear bands but the detailed mechanisms remain largely unclear. It is also not understood how shear bands influence the microstructure and texture evolution during subsequent annealing treatments. Aim of the here presented project is, therefore, to perform a fundamental study on the deformation and recrystallisation mechanisms in these alloys. Samples of different alloy composition will be produced, deformed and annealed. High resolution orientation microscopy techniques in SEM and TEM and 3-dimensional orientation microscopy in a FIB-SEM will then be applied to characterise samples of different deformation and recrystallisation degree. A sound understanding of the deformation and recrystallisation mechanisms is essential for further development of this promising class of materials.