GOALI: Additive Manufacturing of Nano-twinned Metals via Localized Pulsed Electrodeposition (L-PED)

增材制造通过实现从计算机模型逐层生产组件，正在彻底改变制造业。与塑料、聚合物和水凝胶的3D打印相比，工业采用金属增材制造的速度较慢。这项学术与工业联络资助机会（GOALI）项目涉及基础研究，以扩大金属增材制造的规模。这项研究将把重点放在一种特殊类型的金属上，称为“纳米孪晶”金属，它同时具有高强度、高延展性和高导电性。这些特性是由其特殊的微观结构实现的，这与传统金属明显不同。具体来说，在这些金属的原子结构中，形成了专门边界（孪边界，TBs）的平行阵列，其中原子与边界具有镜像对称。这些边界强化了金属。此外，电流可以很容易地通过边界上的镜像原子，使这些材料非常适合于电气应用。这项基础研究将产生一种增材制造工艺，可用于许多行业，如结构应用、电子互连和传感器。这项研究可能会产生一种可行的商业低成本金属3D打印机，可以被学术研究实验室、教育机构和小型制造企业（sme）采用。与工业界在这个目标ali项目上的伙伴关系将促进这种过渡。在本项目中，将对一种新的增材制造工艺进行基础研究，该工艺可以控制双晶片厚度和双晶密度，从而控制机械和电气性能。该工艺基于局部脉冲电沉积工艺。纳米孪晶金属是含有高密度层状纳米级区域的超细晶或细晶金属。这些区域由连贯的双边界划分。纳米孪晶金属具有前所未有的超高强度、高延展性和高导电性。这种大块形式的金属可以通过各种方法合成，包括电沉积、再结晶、相变、溅射沉积和塑性变形处理。然而，目前还没有纳米孪晶金属的增材制造工艺。该项目将利用多物理场模拟和多尺度实验相结合的方法，对局部脉冲电沉积（L-PED）纳米孪晶金属的增材制造进行理论研究。此外，还将利用三维L-PED技术制备纳米孪晶金属，并对打印金属的工艺-结构-性能关系进行研究。

Additive manufacturing is revolutionizing manufacturing by enabling layer-by-layer production of components from computer models. Metal additive manufacturing has been adopted by industry at a slower pace compared to 3D printing of plastics, polymers, and hydrogels. This Grant Opportunities for Academic Liaison with Industry (GOALI) project involves fundamental research to enable expansion of additive manufacturing of metals. The process enabled by this research will be focused on a specialized type of metals, called `nano-twinned' metals, which exhibit simultaneous high strength, high ductility, and high electrical conductivity. These properties are enabled by their special microstructure, which is distinctly different than conventional metals. Specifically, in the atomic structure of these metals, parallel arrays of specialized boundaries (twin boundaries, TBs) form in which atoms have a mirror symmetry with respect to the boundary. These boundaries strengthen the metal. Also, electric current can readily flow through mirror atoms in the boundary, making these materials well-suited for electrical applications. This fundamental research will result in an additive manufacturing process that can be adopted in many industries such as for structural applications, interconnects in electronics, and sensors. This research may result in a viable commercial low-cost 3D printer for metals, which can be adopted by academic research labs, educational facilities, and small manufacturing enterprises (SMEs). The partnership with industry on this GOALI project will facilitate such transition.In this project, fundamental research will be conducted on a new process for additive manufacturing of metals with controlled twin lamella thickness and twin density, and hence controlled mechanical and electrical properties. The process is based on a localized pulsed electrodeposition process. Nano-twinned metals are ultrafine-grained or fine-grained metals that contain a high density of layered nanoscale regions. These regions are divided by coherent twin boundaries. Nano-twinned metals have an unprecedented combination of ultrahigh strength, high ductility, and high electrical conductivity. This type of metal in bulk form can be synthesized via various approaches including electrodeposition, recrystallization, phase transformation, and sputter deposition, and plastic deformation processing. However, there is no current process for additive manufacturing of nano-twinned metals. This project will develop a theoretical understanding of additive manufacturing of nano-twinned metals by localized pulsed electrodeposition (L-PED) using combined multi-physics simulation and multi-scale experiments. In addition, nano-twinned metals will be manufactured by 3D L-PED and the process-structure-property relationship of the printed metals will be investigated.