Manufacturing of near net shape bulk nanostructured materials

与微米级材料相比，纳米材料(即粒度分布在1到100 nm之间的材料)的主要兴趣在于可以获得的新的机械和化学性能：卓越的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。纳米材料在性能方面可能获得的收益在所有技术部门都产生了影响。阻碍它们广泛应用的实际挑战是能否获得以具有竞争力的价格制造无懈可击的大型大宗部件的工艺。近净板形加工路线大大降低了材料和加工成本，并减少了在加固后作业期间产生关键缺陷的可能性，这将有助于将其商业化和实施。然而，纳米材料的近净形状加工工程还处于起步阶段，还需要进一步了解材料的行为和工艺条件的优化。因此，本研究方案旨在研究三种制备近净形状块体纳米结构材料的工艺：放电等离子烧结轧制、电火花焊自由成形和可控短路金属惰性气体保护焊。前两条工艺路线将开发面向运输行业的块状纳米结构铝系统，而后者将专注于用于耐磨应用的纳米复合材料。该项目将产生商业上可行的方法，能够以工业负担得起的成本生产具有几何形状的大规模块状纳米结构材料。

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.