The present work involves the numerical simulation and experimental study on the surface roughness evolution and heterogeneous plastic deformation (strain localization and concomitant surface morphology evolution) in grain scale of micro deep drawn parts of austenitic stainless steel (ASS) 304 foils. A three-dimensional modeling framework was used to simulate the micro deep drawing (MDD) process. The simulation involved the development of a Voronoi-based polycrystalline geometry model (VPGM), a multi-stress-strain response model, and a crystal plasticity finite element methods (CPFEM) model. The results indicate that CPFEM model exhibits higher accuracy in the localized stress and strain, thickness distribution fluctuation and surface roughness evolution of the fabricated parts compared to multi-stress-strain response model. Therefore, the plastic deformation heterogeneity in MDD is in-depth discussed based on CPFEM model. The results show that the coarse-grained foils correspond to the intense strain localization, which is the main cause of surface roughening. Considering the average grain size is close to the thickness of ASS foils, mounding features on the rough surface may readily develop further into potentially fractured sites during deformation. On the other hand, crystal orientation influence plastic deformation by affecting the slip behavior of materials. The effect of crystal orientations including {011} 〈211〉 (Brass), {011} 〈100〉 (Goss), and {112} 〈110〉 components on deformation is discussed. The results indicate a strong correlation between the magnitude of the Schmid's factor and the ease of deformation. Additionally, variations in Schmid's factor across different directions result in differences in deformation accumulation, which affects the thickness distribution along the radial direction and the distribution of earrings and wrinkles along the circumferential direction of the fabricated micro parts.

中文翻译：

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奥氏体不锈钢在微拉深过程中的表面粗糙度演变和异质塑性变形：建模和实验

目前的工作涉及奥氏体不锈钢 (ASS) 304 箔片微拉深零件晶粒尺度的表面粗糙度演变和异质塑性变形（应变局部化和伴随的表面形貌演变）的数值模拟和实验研究。使用三维建模框架来模拟微拉深（MDD）过程。模拟涉及开发基于 Voronoi 的多晶几何模型 (VPGM)、多应力应变响应模型和晶体塑性有限元方法 (CPFEM) 模型。结果表明，与多应力应变响应模型相比，CPFEM 模型在制造零件的局部应力和应变、厚度分布波动和表面粗糙度演变方面表现出更高的精度。因此，基于CPFEM模型对MDD中的塑性变形不均匀性进行了深入讨论。结果表明，粗晶箔对应于强烈的应变局部化，这是表面粗糙化的主要原因。考虑到平均晶粒尺寸接近 ASS 箔的厚度，粗糙表面上的堆积特征在变形过程中很容易进一步发展成潜在的断裂部位。另一方面，晶体取向通过影响材料的滑移行为来影响塑性变形。讨论了包括{011}<211>（黄铜）、{011}<100>（高斯）和{112}<110>成分在内的晶体取向对变形的影响。结果表明施密德因子的大小与变形的容易程度之间存在很强的相关性。此外，施密德因子在不同方向上的变化会导致变形积累的差异，从而影响所制造的微型零件沿径向的厚度分布以及沿圆周方向的耳环和皱纹的分布。