不同晶面杨氏模量（或弹性张量）将引起晶格弹塑性变形的各向异性，进而显著影响多晶体金属塑性变形过程的位错演变、织构变化和加工硬化行为。由于受现有实验研究方法的限制，目前的研究主要集中在弹塑性自洽模型和晶体塑性有限元模拟等方面，还无法突破析出强化型铝合金塑性晶格各向异性行为实验研究的技术瓶颈。因此，本项目拟运用申请人最新提出的X射线衍射(XRD)线形宽化改良分析方法，并结合电子背散射衍射（EBSD）、透射电子显微镜（TEM）和电阻率测量等定性、定量表征技术，研究Al-Zn-Mg-Cu合金中析出相特征对塑性变形过程晶格各向异性行为的影响，探究具有不同析出相特征的合金中位错演变、织构与晶格各向异性的交互作用机制；基于实验和模型分析，揭示塑性晶格各向异性对合金加工硬化行为的影响机理，为深入理解析出强化型铝合金弹塑性转变及加工硬化机理提供新的理论依据，同时拓展XRD线形宽化分析的应用理论基础。

The Young's modulus of different crystal planes (or elastic tensor) will result in the anisotropy of lattice elastic-plastic deformation, which will significantly affect the dislocation evolution, texture development and work hardening behavior of polycrystalline metals during plastic deformation. Due to the limitations of existing techniques and approaches for experimental investigation, the current researches focus on elastoplastic self-consistent model and crystal plasticity finite element simulation. It did not overcome the technical circumstances in the experimental studies of plastic lattice anisotropy of precipitation-strengthened Al alloy yet. Therefore, the present project will employ the improved X-ray diffraction (XRD) line profile breadth analysis approach proposed by the applicant recently and the qualitative and quantitative characterization techniques, for instance electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and electrical resistivity measurement. The influences of precipitate characteristics on plastic lattice anisotropy behaviors during plastic deformation are to be studied in Al-Zn-Mg-Cu alloy accordingly. The interaction mechanisms among dislocation evolution, texture and plastic lattice anisotropy in Al-Zn-Mg-Cu alloy with different precipitate characteristics will also be investigated. Then, the influence mechanisms of plastic lattice anisotropy on strain hardening are to be revealed by means of experimental and model analyses. This program will provide new theoretical knowledge for the in-depth understanding of elastic-plastic transformation and strain hardening mechanisms in precipitation-strengthened Al alloys. Further, the fundamental theory for the application of XRD line profile breadth analysis approach is also to be extended.