AHSS: Multi-scale Modeling of Deformation Mechanism for Design of New Generation of Steels

该奖项的研究目标是开发适当的计算方法，用于模拟先进高强度钢（AHSS）的相变和变形机制。一个新的家庭的扩展时间尺度模拟方法，如扩散分子动力学和自由端轻推弹性带将被用来探测新的微观结构特征和新的强化机制AHSS通过多尺度建模方法，耦合的量子化学，原子和介观性质的变形和相变机制。扩散，位移以及耦合扩散位移过程将在一个统一的数学框架下处理。每一种新的强化机制将以其自身的速率依赖性（激活能和激活体积）和应变硬化定律为特征。可提供的内容包括软件模块、参数公式和属性表、研究成果出版物和工程专业学生教育。如果成功的话，本研究的结果将有助于在不增加成本的情况下提高钢的强度-塑性包络线，这是第三代AHSS设计的主要标准。开发的新材料概念和模型将提供给学术界和工业界。我们计划将我们的计算方法和模拟结果放在一个开放的网站上。我们还将把新材料的概念、建模方法和软件程序整合到宾夕法尼亚大学和俄勒冈州立大学的本科和研究生课程中。特别是，应用原子和相场的方法在这个程序中开发的建模钢的相变和塑性变形的新模块将被引入到现有的本科和研究生课程。

The research objective of this award is to develop appropriate computational methods for modeling phase transformation and deformation mechanisms in advanced high-strength steels (AHSS). A new family of extended-timescale simulation methods such as diffusive molecular dynamics and free-end nudged elastic band will be employed to probe the novel microstructural features and new strengthening mechanisms in AHSS through a multi-scale modeling approach that couples the quantum chemical, atomistic and mesoscopic nature of deformation and phase transformation mechanisms. Diffusive, displacive as well as coupled diffusive-displacive processes will be treated under a unified mathematical framework. Each new strengthening mechanism will be characterized by its own rate dependence (activation energy and activation volume) and strain-hardening law. Deliverables include software modules, parametric formulas and property tables, publications of research results and engineering student education. If successful, the results of this research will aid the efforts to enhance the strength - ductility envelop of steels without increasing the cost, the main criterion for the design of third generation AHSS. New material concepts and models developed will be made available to both academic and industrial communities. We plan to place our computational methods and simulation findings on an open web site. We will also integrate the new materials concepts, modeling methods, and software programs into undergraduate and graduate curricula at Penn and OSU. In particular, new modules on applying atomistic and phase field methods developed in this program for modeling phase transformation and plastic deformation in steels will be introduced to the existing undergraduate and graduate courses.