剧烈塑性变形条件下金属间化合物相变研究

项目名称： 剧烈塑性变形条件下金属间化合物相变研究

项目编号： No.51271107

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 操光辉

作者单位： 上海大学

项目金额： 80万元

中文摘要： 剧烈塑性变形（Severe plastic deformation, SPD）使金属和合金产生晶粒细化、无序或非晶等独特的结构变化，成为制备性能优异的超细晶及纳米晶块体材料的有效方法。迄今，剧烈塑性变形条件下金属间化合物相变机理仍不清楚。本项目拟对金属间化合物施加高达8 GPa的压力，采用高压扭转（High pressure torsion, HPT）剧烈塑性变形方法，以YCu和TiAl金属间化合物为研究对象，研究金属间化合物剧烈塑性变形行为，进而研究剧烈塑性变形高应力、高应变、高位错密度和高空位浓度条件下诱发产生相变的种类、形核、热力学和动力学规律，阐明剧烈塑性变形条件下YCu金属间化合物中位移型马氏体相变和TiAl金属间化合物中扩散型相变的形成机制，构建剧烈塑性变形条件下金属间化合物相变的晶体学及微观结构与力学行为本构关系的物理模型。本项目可为改善金属间化合物塑性提供理论基础。

中文关键词： 金属间化合物；相变；剧烈塑性变形；微观结构；透射电镜

英文摘要： Severe plastic deformation (SPD) has become a very attractive method to produce bulk submicro- to nanocrystalline metals and alloys exhibiting new mechanical and functional properties for advanced applications. The structural features of SPD are characterized not only by grain refinement but often also by disordering or even amorphization. So far, little is known about phase transformations in intermetallic compounds under SPD. Therefore, it is the aim of the project to study the deformation behavior of intermetallic compounds under SPD, and then the type, nucleation and kinetics of SPD-induced phase transformations occurring under high level of stresses, high strain, high dislocation density and high vacancy concentration. The method used will be high pressure torsion (HPT). Intermetallic compounds are torsion strained under a quasi-hydrostatic pressure up to 8 GPa. Focus will be put on two intermetallic systems, YCu and a TiAl-based multiphase alloy. Formation mechanisms of the displacive martensitic transformation in YCu and the diffusive transformation in titanium aluminide will be elucidated under SPD. Based on the above investigations, the physical models for the constitutive relations between the crystallography, microstructure and mechanical behavior are to be established. It may also allow the findings

英文关键词： Intermetallic compounds；Phase transformation；Severe plastic deformation；Microstructure；Transmission electron microscopy