Chapter 2 - Deformation Inhomogeneity

Abstract

Spatially and temporally distributed in deformable materials, inhomogeneous deformation is a most ubiquitous phenomenon in deformation-based materials processing. Actually, homogeneous deformation only ideally exists in the theoretical assumption made for simplified analysis of deformation operations. The inhomogeneity of deformation is directly related to the occurrence and propagation of various external and internal defects and thus directly determines the accuracy in shape and dimension changes and property and performance tailoring. In-depth understanding of deformation inhomogeneity and modeling and controlling of inhomogeneous deformation is necessary for improving forming limit, process performance, and product quality. In this chapter, deformation inhomogeneity is first described and the multiple deformation mechanisms and root causes of inhomogeneous deformation are then elucidated and discussed from both microstructure- and residual stress-related intrinsic parameters and external loading conditions perspectives. In addition, materials and processing models for accurately describing and predicting inhomogeneous deformation are then introduced. Finally, how to control inhomogeneous deformation and even positively coordinate the spatial inhomogeneous deformation flow is discussed from the perspectives of material properties and loading conditions.