Abstract Enhanced workability, as characterized by the magnitude and heterogeneity of accommodated plastic strains during sheet processing, is demonstrated in high Si content Fe-Si alloys containing 4 and 6.5 wt% Si using two single-step, simple-shear deformation techniques – peeling and large strain extrusion machining (LSEM). The model Fe-Si material system was selected for its intrinsically poor material workability, and well-known applications potential in next-generation electric machines. In a comparative study of the deformation characteristics of the shear processes with conventional rolling, two distinct manifestations of workability are observed. For rolling, the relatively diffuse and unconfined deformation zone geometry leads to cracking at low strains, with sheet structures characterized by extensive deformation twinning and banding. Workpiece pre-heating is required to improve the workability in rolling. In contrast, peeling and LSEM produce continuous sheet at large plastic strains without cracking, the result of more confined deformation geometries that enhances the workability. Peeling, however, results in heterogeneous, shear-banded microstructures, pointing to a second type of workability issue – flow localization – that limits sheet processing. This shear banding is to a large extent facilitated by unrestricted flow at the sheet surface, unavoidable in peeling. With additional confinement of this free surface deformation and appropriately designed deformation zone geometry, LSEM is shown to suppress shear banding, resulting in continuous sheet with homogeneous microstructure. Thus LSEM is shown to produce the greatest enhancement in process workability for producing sheet. These workability findings are explained and discussed based on differences in process mechanics and deformation zone geometry.

中文翻译：

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通过大剪切变形提高高硅含量电工钢板材生产的可加工性

摘要 在含 4 和 6.5 重量％硅的高硅含量 Fe-Si 合金中，使用两种单步、简单剪切变形技术——剥离和剪切变形，证明了增强的可加工性，其特征在于在板材加工过程中所适应的塑性应变的大小和不均匀性。大应变挤压加工 (LSEM)。选择模型 Fe-Si 材料系统是因为其固有的材料可加工性较差，并且在下一代电机中具有众所周知的应用潜力。在与传统轧制的剪切过程的变形特性的比较研究中，观察到两种不同的可加工性表现。对于轧制，相对扩散和无限制的变形区几何形状导致在低应变下开裂，板材结构以广泛的变形孪晶和条带为特征。需要对工件进行预热，以提高轧制的可加工性。相比之下，剥离和 LSEM 在大塑性应变下生产连续板而不会开裂，这是更受限的变形几何形状的结果，提高了可加工性。然而，剥离会导致异质、剪切带状微观结构，表明第二种可加工性问题——流动定位——限制了板材加工。这种剪切带在很大程度上是由片材表面不受限制的流动促进的，在剥离时是不可避免的。通过对这种自由表面变形的额外限制和适当设计的变形区几何形状，LSEM 被证明可以抑制剪切带，从而产生具有均匀微观结构的连续板材。因此，LSEM 显示出对生产板材的工艺可加工性产生最大的增强。根据工艺力学和变形区几何形状的差异解释和讨论了这些可加工性结果。