剧烈塑性变形：不仅是晶粒细化

摘要

剧烈塑性变形在生产超细晶材料方面已经显示了巨大的潜力。虽然大量的研究集中在晶粒细化上，等通道转角挤压和高压扭转等剧烈塑性变形过程正在越来越多地被应用于其他领域诸如粉末固结，利用变形引发相变制作新颖结构与成分，获得多相及多尺度材料以及固态回收技术。本文引用我们近十年来的研究成果以介绍剧烈塑性变形在晶粒细化之外的诸多应用。特别是利用剧烈塑性变形颗粒固结来制取大块铝、钛、铝/钛双相合金和铝基纳米复合材料，利用机械激活和强制合金化来获得包括面心立方在内的新型钛结构，利用剧烈塑性变形引发的相变来制备纳米晶beta钛合金，以及利用等通道转角挤压来固态回收钛合金切削料。最后，对存在的挑战和机会进行了探讨。%Severe plastic deformation ( SPD) based processes have shown great potential in producing bulk ultrafine grained materials. Although most of the research has been focused on grain refinement, SPD processes such as equal channel angular pressing (ECAP) and high pressure torsion (HPT) are increasingly used to achieve other objectives including powder consolidation, creation of novel structures and compositions through deformation induced phase transformations, production of multi-phase and/or multi-scale materials, and solid-state recycling. Using examples from our research in the past decade, various SPD applications other than pure grain refinement are presented. In particular, bulk pure Al and Ti, Al/Ti alloys, Al nanocomposites are synthesised by SPD consolidation of particles, unusual structures including fcc are created in Ti by mechanical activation and forced alloying, nanocrystalline beta Ti alloys are produced with the assistance of SPD induced phase transformation, and Ti machining chips are recycled in the solid state. Challenges and opportunities are discussed.