Multi-scale Microstructure Prediction in Thermo-mechanical Processing

本研究项目旨在(1)建立一个系统的方法，通过在多个长度尺度上建模来预测金属热机械加工过程中的微观结构演变；(2)以有效的数值算法的形式开发和实现该方法；(3)应用该算法研究晶粒生长和再结晶的基本微观结构现象。这种方法优于当前工业实践中流行的经验建模技术。提出的多尺度方法将被实施到一个模拟系统中，该系统由基于连续体的耦合热力学模型、多尺度建模界面和介观微观结构模型组成。仿真输入包括加工条件、材料宏观和细观性能以及初始微观结构特征。模拟序列的最终输出是得到的微观结构。这个为期三年的项目将包括三个主要阶段：第一阶段，包括(I)开发一个计算存储能量作为应变和应力函数的模型，（ii）开发二维和三维蒙特卡罗（MC）模型，用于模拟静态再结晶和正常晶粒生长，以及（iii）应用这些模型研究各种微观结构现象的基本物理。在该项目的第二阶段，物理和MC域之间的长度和时间尺度转换将通过使用纯材料进行晶粒生长实验来进行。在第三阶段，将进行纯材料的冷镦和随后的退火试验。这些实验中测量的晶粒尺寸将用于验证通过多尺度建模进行微观结构预测的方法。通过开发、实施和验证金属微观结构现象建模的多尺度方法，该项目将以与工业相关的方式推进微观结构预测的最新技术。一个行业合作伙伴（McWilliams Forge Co.）将参与该项目。此外，史蒂文斯理工学院（SIT）的本科生和研究生都将参与这项研究，并将努力包括女性和代表性不足的少数民族学生。

This research project aims at (i) establishing a systematic methodology for predicting the microstructure evolution during thermo-mechanical processing in metals by modeling at multiple length scales, (ii) developing and implementing the method in the form of efficient numerical algorithms, and (iii) applying the algorithms to study the fundamental microstructural phenomena of grain growth and recrystallization. This approach is superior to the empirical modeling techniques prevalent in current industrial practice.The proposed multi-scale methodology will be implemented into a simulation system thatconsists of continuum-based coupled thermo-mechanical models, a multi-scale modelinginterface and mesoscopic microstructural models. The simulation input includes the processing conditions, macroscopic and mesoscopic material properties and initial microstructure features. The final output of the simulation sequence is the resulting microstructure.The proposed three-year project will comprise three major phases:Phase I, involves (i) the development of a model for computing the stored energy as a function of strain and stress, (ii) the development of two- and three-dimensional Monte Carlo (MC) models for simulating static recrystallization and normal grain growth, and (iii) the application of these models to study the fundamental physics of various microstructural phenomena. In Phase II of this project, the length and time scale conversions between the physical and MC domains will be performed by conducting grain growth experiments with a pure material. In Phase III, cold upsetting and subsequent annealing tests of a pure material will be carried out. The grain sizes measured in these experiments will be used to validate the proposedmethodology of microstructure prediction through multi-scale modeling. Through the development, implementation and validation of a multi-scale approach for modeling microstructure phenomena in metals, this project will advance the state of the art in microstructure prediction in an industrially relevant way. An industry collaborator (McWilliams Forge Co.) will participate in the project. Furthermore, both undergraduate and graduate students at Stevens Institute of Technology (SIT) will be involved in the research, with an strong effort made towards including female and underrepresented minority students.