Manufacturing of near net shape bulk nanostructured materials

纳米材料，即粒度分布在1至100 nm范围内的材料，与微米级对应物相比，其主要兴趣在于可实现的新颖机械和化学性能：上级静态和动态机械强度、超塑性、高应变率流动性、增强的耐腐蚀性和耐磨性。纳米材料可能获得的特性在所有技术领域都产生了巨大的影响。阻止其广泛应用的实际挑战是以具有竞争力的价格制造无缺陷的大型散装组件的工艺的可用性。近净形加工路线能够显著降低材料和加工成本，并降低在固结后操作期间引入关键缺陷的可能性，这将有助于其商业化和实施。然而，纳米材料的近净形加工工程仍处于起步阶段，对材料行为的进一步理解和加工条件的优化仍有待完成。因此，本研究建议的目的是研究三种方法来制造近净形状的散装纳米结构材料：放电等离子烧结轧制，自由成形，使用电火花焊接和控制短路金属惰性气体保护焊。前两种工艺路线将开发针对运输行业的块状纳米结构Al系统，而后者将专注于用于磨损应用的纳米复合材料。该项目将产生商业上可行的工艺，能够以行业可承受的成本生产大规模的几何形状的散装纳米结构材料。

The major interest in nanomaterials, i.e. materials with a grain size distribution ranging from 1 to 100 nm, resides in the novel mechanical and chemical properties achievable compared to their micron-scale counterparts: superior static and dynamic mechanical strength, superplasticity, high strain rate flowability, enhanced corrosion and wear resistance. The possible gain in properties obtainable with nanomaterials creates an enthousiams in all technological sectors. The actual challenge preventing their utilization at large is the availability of processes to fabricate flawless large-scale bulk components at a competitive price. The near-net shape processing route enables significant material and processing cost reduction and reduces the possibility of introducing critical flaws during post-consolidation operations, which would help contributing to their commercialization and implementation. However, the engineering of near-net shape processing of nanomaterials is at its infancy and further understanding of the material's behavior and optimization of the processing conditions remains to be done. The present research proposal is therefore aimed at studying three processes to fabricate near net-shape bulk nanostructured materials: spark plasma sinter rolling, freeforming using electrospark welding and controlled short circuit metal inert gas welding. The two former processing routes will developed bulk nanostructured Al systems targeting the transportation industry, while the later will focus on nanocomposites for wear applications. This project will yield commercially viable processes capable of producing large-scale bulk nanostructured materials in geometries and at cost affordable to the industries.