Practice and theory in the design of martensitic steels

早在欧洲铁器时代的第一世纪，就有关于钢淬火的文字记载。在荷马史诗中我们发现“...就像铁匠用短柄斧或大斧头...把嘶嘶作响的刀刃深深地插进冰冷的水中：钢的力量从何而来……“淬火和回火钢的考古证据存在于几个世纪前。回火被认为是必要的，以减轻淬火钢的极端硬度和脆性。另一方面，低成本的硬化马氏体和硬拉珠光体钢已经达到强度极限。我们建议推动包络，采取根本性措施，取消回火步骤，并设计新的多相淬火，坚韧，精益（低成本，资源效率）钢（MATLeS）。关键是利用最近获得的体心立方金属塑性的理解;加工硬化;溶解碳，位错和金属碳氮化物之间的相互作用。这将与新的国家的最先进的实验技术放在一起：特别是旋进电子显微镜和拉伸应力松弛。在强大的组合，这些将为我们提供手段来操纵和利用分级板条马氏体显微组织（HiLaMM）。我们设计的新钢材将具有出色的绿色证书：资源效率，可回收性，高强度重量比。我们的愿景是实现电动汽车的经济性、海上风电场结构部件的轻量化以及用于海底和土木工程项目的超强电缆。我们的成果将为材料科学的现代理论提供信息，推进世界上一个突出的科学问题的解决方案：什么是加工硬化的本质？(Why我能不能把你刚才弄弯的拨火棍弄直？）

Written records of the quenching of steel exist as early as the first century of the European Iron Age. In Homer we find "... As when the smith an hatchet or a large axe ... plunges the hissing blade deep in cold water: whence the strength of steel ..." Archeological evidence for quenched and tempered steel exists from several centuries earlier. Tempering has been regarded as essential in order to mitigate the extreme hardness and brittleness of as-quenched steel. On the other hand the strength limit has been reached in low cost hardened martensitic and hard-drawn pearlitic steels. We propose to push the envelope making the radical move of dispensing with the tempering step and designing new multiphase, as quenched, tough, lean (low cost, resource efficient) steel (MATLeS). The key is to exploit recently acquired understanding of the plasticity of body centered cubic metals; work hardening; and interplay between dissolved carbon, dislocations and metal carbonitrides. This will be put together with novel state-of-the-art experimental techniques: in particular precession electron microscopy and tensile stress relaxation. In powerful combination these will furnish us with the means to manipulate and exploit the hierarchical lath martensite microstructure (HiLaMM). The new steels we design will have excellent green credentials: resource efficiency, recyclability, high strength-to-weight ratio. Our vision is toward the electric vehicle economy, light-weighting of structural offshore wind farm components and super-strong cables for undersea and civil engineering projects. Making full-circle, our outcomes will inform modern theories in materials science, advancing solutions to one of the world's outstanding scientific questions: what is the nature of work hardening? (Why can I not straighten the poker you have just bent?)