Bridging the gap - a new generation process model for steels by modelling across different length scales

这个联合UBC-McMaster项目汇集了一群加拿大领先的计算材料科学家，他们的目标是基于计算机建模技术开发新的过程模型，跨越原子到宏观材料的长度尺度。具体来说，这个项目涉及钢中奥氏体到铁素体的转变。这种转变构成了主要的冶金工具，用于产生复杂的显微组织，使先进的高强度钢具有优越的性能。这些新钢材主要在汽车应用中具有重要意义，它们可以设计出重量轻、因此更省油的车辆。管道和建筑行业在开发新钢种方面也取得了类似的进展。这些新型钢需要增加合金添加水平（例如Mn， Cr）来调整相变，并且作为增值产品，与传统钢相比，它们需要显着增加对加工窗口的控制（例如在热轧机中）。因此，过程模型对于减少属性变化和提高加拿大钢铁生产商和用户保持全球竞争力的生产力至关重要。为这些新钢开发可靠的工艺模型的一个特别挑战是，合金元素对奥氏体到铁素体转变的影响从基本角度来看知之甚少。因此，提出的建模方法采用了跨不同长度尺度建模的创新方法。过程模型是在宏观长度尺度上制定的，而基础物理参数是由原子尺度上的现象产生的。因此，将涵盖不同长度尺度的建模工具组合在一起，即从合金元素与移动转换前沿相互作用的从头算原子建模开始，建模长度尺度将通过微观结构（即所谓的中观尺度）尺度逐渐增加到工业产品的宏观尺度。提出的方法的一个组成部分是用实验和工业数据验证模型。

This joint UBC-McMaster project brings together a group of Canada's leading Computational Materials Scientists with the goal of developing new process models based on computer modelling techniques spanning the atomistic to the macroscopic materials length-scales. Specifically, this project deals with the austenite-to-ferrite transformation in steels. This transformation constitutes the primary metallurgical tool used to generate the complex microstructures giving the superior properties of advanced high-strength steels. These new steels are primarily of significance for automotive applications where they enable the design of light-weight and, therefore, more fuel efficient vehicles. Similar developments in developing new steel grades are seen for pipelines and in the construction sector. These new steels require an increased level of alloying addition (e.g. Mn, Cr) to tailor the phase transformation and, as a value-added product, they require a significantly increased control of processing windows (e.g. in a hot mill) as compared to conventional steels. Thus, process models are critical to reduce property variability and to increase productivity that Canada's steel producers and users remain globally competitive. A particular challenge in developing a reliable process model for these new steels is that the effect of alloying elements on the austenite-to-ferrite transformation is poorly understood from a fundamental perspective. Thus, the proposed modelling approach employs an innovative methodology by modelling across different length scales. Process models are formulated on a macroscopic length scale while underlying physical parameters result from phenomena on the atomistic scale. Thus, modelling tools will be combined that cover different length scales, i.e. starting from ab-initio atomistic modelling of the interaction of alloying elements with the moving transformation front the modelling length scale will be gradually increased via the scale of the microstructure (i.e. so-called meso-scale) to the macro-scale of the industrial product. An integral part of the proposed approach is to validate the models with experimental and industrial data.