Microstructure Evolution and Mechanical Behaviour of Advance Structural Materials

材料的性能，如强度和延展性，强烈依赖于材料的内部结构(微观结构)。本工作的目的是为了更好地了解在先进钢的加工和使用过程中控制组织演变的过程。最终，这将使我们能够调整加工参数(例如温度和变形)，从而生产出具有良好微观结构和性能的材料。第一个领域是低碳钢的相变领域。众所周知，铁以两种形式存在：一种是被称为奥氏体的高温形式，另一种是被称为铁素体的低温形式。合金元素的加入对奥氏体铁素体冷却转变的动力学有很大的影响。尽管这一转变具有重要意义，但合金化元素对转变的影响机制仍然知之甚少。拟议的工作将涉及高度受控的实验，这将使我们能够更好地了解合金元素的影响。为了开发经过实验验证的相变模型，将利用原子尺度表征领域的最新突破。*第二个感兴趣的领域是热机械加工。人们对热机械工艺(如热轧)的极大兴趣，是因为这些工艺可以细化组织，进而提高强度和韧性。在这项拟议的工作中，将对一系列实验合金进行研究，以确定在热轧过程中微观组织发生的关键变化。一旦了解了这些变化，基于物理的多道次变形模型将被开发并用于优化加工条件。*作为本提案的一部分，将调查的第三个专题是多个长度尺度的微结构工程。除了微观结构中的固有尺度外，还可以通过引入组成梯度(大约一毫米)或通过引入结构增强(大约一厘米)来引入新的尺度。这项拟议的工作将探索利用这些长度刻度来生产具有新颖性能组合的材料的潜力。*总共将在对加拿大工业非常重要的领域培训10名高度合格的个人。毕业生将有资格在钢铁、汽车和制造业工作。

Material properties such as strength and ductility are strongly dependent on the internal structure (microstructure) of the material. The objective of the present work is to provide a better understanding of the processes which control the microstructure evolution during the processing and use of advanced steels. Ultimately, this would permit us to adjust the processing parameters (e.g. temperature and deformation) so as to produce a material with a favourable microstructure and consequently, favourable properties.******The proposed work has three main thrusts. The first of these is the area of phase transformations in low carbon steels. It is well known that iron, Fe, exists in two forms; a high temperature form known as austenite and a low temperature form known as ferrite. The addition of alloying elements has been shown to have a strong effect on the kinetics of the transformation from austenite to ferrite on cooling. In spite of the great significance of this transformation, the mechanism by which the alloying elements affect the transformation is still poorly understood. The proposed work would involve highly controlled experiments which would permit us to better understand the effect of the alloying elements. Recent breakthroughs in the area of characterization at the atomic scale will be exploited in order to develop experimentally-validated phase-transformation models. ******The second area of interest is that of thermomechanical processing. The great interest in thermomechanical processes, such as hot-rolling, is due to the fact that these permit the refinement of the microstructure which, in turn, leads to improvements in strength and toughness. In the proposed work a series of experimental alloys will be investigated in order to determine key changes that occur within the microstructure during hot-rolling. Once these changes are understood, a physically-based model of multi-pass deformation will be developed and employed to optimize processing conditions. ******The third topic which will be investigated as part of this proposal is the engineering of microstructures at multiple length scales. In addition to the intrinsic scales within the microstructure, one can introduce new scales by introducing composition gradients (of the order of a millimetre) or by introducing architectured reinforcement (on the order of a centimeter). The proposed work will explore the potential of exploiting these length scales in order to produce materials with novel combinations of properties.***In total, 10 highly qualified individuals will be trained in areas of great importance to the Canadian industry. The graduates will be qualified to work in the steel, automotive and manufacturing sectors.********