Sculpting Energy Landscapes in Materials: Theory, Experiment and Application

人类发展的一个基本特征是对材料的掌握，从铁匠将金属敲打成武器，再到机器人为彻底改变我们通信的电子设备一层层地存放原子。今天，受有限的矿产资源和环境需求的限制，我们的未来需要更多的掌握，实际上是从少到多。我们已经面临着这些挑战--延长发电厂的寿命，制造更安全、更轻的汽车，以及寻找更高能量密度的电池解决方案。要使材料具有更好的性能，问题的核心是了解和控制其内部结构。一种材料结构跨越亚纳米到毫米长度的尺度，通过由边界相互连接的相来填充之间的空间，这就是微结构。材料科学家和工程师很早就知道晶界对工程性能的重要性。在一些材料中观察到了特殊的边界，当损坏时可以自我修复，这可以防止结构材料的故障。材料表演中的颗粒边界角色类似于电影喜剧中的多门走廊设置，许多演员进入、停留或迅速离开，取决于他们是否需要见某人或逃离某事。然而，与走廊不同的是，我们远远无法识别和掌握真实材料中可能出现的哪怕一小部分晶界情景，因为这些结构很难观察、描述和控制。*当控制性能的结构不变时，材料是有用的。然而，材料永远不会真正处于平衡状态，而是被“催眠”进入亚稳态，这些亚稳态由化学和结构特征的分布组成，这些特征共同构成了一幅能量图景。在最简单的意义上，当我们对其进行处理时，这种景观是自组织的，即绘制钢琴钢丝重新定位内部晶体，溶解相并形成内部缺陷的图案。当能量通过走廊/门结构时，晶界也会发生变化。*这项研究将首次研究含有晶界的金属在被皇后学院的一种新的高能束源推入高能量状态时是如何消耗能量的。四名研究生将学习光束如何雕刻微结构的能量图景，创造新的和独特的特征，有助于更好地理解晶界结构。这项工作将支持加拿大技术部门在极端环境中运行的材料应用，如核反应堆、外层空间系统和加拿大未来的高铁。

An essential feature of humanity's development has been its mastery of materials, from blacksmiths pounding metal into weapons to robots depositing atoms layer-by-layer for the electronic gadgets revolutionizing our communications. Today, constrained by finite mineral resources and environmental necessity, our future demands even greater mastery, in effect more from less. We are already facing these challenges - extending the lives of power plants, building safer and lighter vehicles, and searching for higher energy density solutions in batteries. At the heart of the problem to make materials perform better is to understand and control its internal structure. A materials structure spans the sub-nanometer to millimeter length scales with space filled in-between by phases interconnected by boundaries that together is the microstructure. Materials scientists and engineers have known for a long time the importance of grain boundaries on engineering properties. Special boundaries have been observed in some materials that self-heal when damaged, which could prevent failures in structural materials. The grain boundaries role in materials performance is analogous to the multiple-door hallway set-up in film comedies, where many actors enter, hang-out, or quickly leave, depending upon whether they need to meet someone, or escape from something. Unlike hallways though, we are far away from being able to identify and master even a fraction of the grain boundary scenarios possible in real materials, because these structures are difficult to observe, describe, and control.******Materials are useful when the structures that control properties do not change. However, materials are never truly at equilibrium and are instead “lulled” into metastable states consisting of a distribution of chemical and structural features that together constitute an energy landscape. In the simplest sense this landscape self-organizes when we do work on it, i.e. drawing piano wire re-orients internal crystals, dissolves phases and patterns internal defects. Grain boundaries change too, as energy ebbs and flows through its hallway/door structure.******This research will for the first time study how metals containing boundaries dissipate energy when they are pushed into highly energized states using a new high-energy beam source at Queen's. Four graduate students will study how the beam sculpts the energy landscape of the microstructure creating new and distinctive features that will help better understand the grain boundary structure. The work will support materials applications in Canada's technology sectors operating in extreme environments such as nuclear reactors, outer space systems, and Canada's future high-speed train.