Deformation Processing: Crystallographic Texture Evolution and Shear Band Formation

可加工性通常定义为变形程度， 可以在特定的变形处理操作中实现 没有失败。 故障可能与基本材料有关 裂纹或断裂现象，但也可能是任何其他 不良状况，例如缺乏模具填充或表面不良 说完 影响混凝土工作性的主要因素 材料是：（1）外部过程变量的应力， 温度、应变、应变速率、摩擦和热传递 边界条件及其演变;（2）内部 微观结构变量，例如孔隙率、晶体学 变形局部化及其演化 在韧性破坏中。 虽然人们已经相当重视 开发用于预测与所述缺陷相关联的缺陷的能力。 在变形加工操作中孔隙的增长， 在纳入发展方面， 其他重要的微观结构特征 数学模型 具体而言，需要将 由于晶体结构和变形的影响 定位与失败 该项目旨在开发精确的各向异性热- 弹粘塑性本构方程和计算 非弹性变形的建模和模拟方法 由于晶体滑移和面心孪晶 立方和六方密堆积合金。 计算 能力将是有用的，在模拟的发展， 各向异性由于晶体织构的演变，和 材料加工缺陷的发展与 在低和高的大变形局部剪切带 同源温度 数学模型应该是有用的 在设计和分析各种冷热变形 处理操作。 这种模式将允许更快，更 精确设计工具和程序以形成金属零件。

Workability is often defined as the degree of deformation that can be achieved in a particular deformation processing operation without failure. Failure may be the basic material related phenomena of cracking or fracture, but it could also be any other undesirable condition, for example lack of die fill or poor surface finish. The major factors which influence the workability of a material are: (1) the external process variables of stress, temperature, strain, strain rate, frictional and heat transfer boundary conditions, and their evolution; and (2) the internal microstructural variables, for example porosity, crystallographic texture, deformation localization and their evolution culminating in ductile failure. While considerable attention has been paid to developing a capability for predicting defects associated with the growth of porosity in deformation processing operations, much remains to be done with regard to incorporating the evolution of other important microstructural features in macroscopic mathematical models. Specifically there is need for incorporating the effects due to crystallographic texture and deformation localization and failure. This project is to develop accurate anisotropic thermo- elastic-viscoplastic constitutive equations and computational procedures for modeling and simulation of inelastic deformations due to both crystallographic slip and twinning in face-centered cubic and hexagonal-closed packed alloys. The computational capability will be useful in simulating the development of anisotropy due to the evolution of crystallographic texture, and the development of material processing defects associated with localized shear bands at large deformations at both low and high homologous temperatures. The mathematical models should be useful in the design and analysis of a variety of cold and hot deformation processing operations. Such models will allow the faster and more accurate design of tools and procedures for forming metal parts.