随着高温合金薄壁微构件在航空航天领域的广泛应用，精确预测由于材料高的屈服强度所引起的回弹变形成为亟待解决的难题。本构关系中的强化模型直接影响回弹预测精度，而传统强化理论不包含材料内禀尺度参数，无法解释材料在微尺度循环塑性变形时表现出的尺度效应以及内在物理机制。本申请针对高强材料微尺度下回弹预测理论研究的不足，通过多尺度循环剪切实验、微弯曲实验、理论建模和有限元方法系统研究高温合金超薄板在不同尺度下的循环塑性变形特性和回弹规律，阐明几何尺寸、晶粒大小、取向和分布等因素对循环加载力学响应和微观组织演化的耦合影响，揭示循环塑性行为的尺度效应及内在物理本质，确定不同尺度和变形模式对强化模型有效性的影响规律，建立基于细微观变形机制的跨尺度循环塑性本构模型，实现微尺度回弹的精确预测。该研究对丰富和完善微尺度循环塑性变形行为的认识具有重要理论意义，同时在微塑性成形回弹精确补偿方面具有广阔的工程应用前景。

With the widespread application of superalloy thin-walled microparts in aerospace domain, it is an urgent problem to accurately predict the springback due to the high yield strength of the used material. The hardening model in the material constitutive relation directly affects the prediction accuracy of springback. However, the classical elasto-plastic theory does not possess intrinsic length scale parameter, it is incapable of capturing the size-dependent phenomena of sheet metals at the micro scale and the underlying physical mechanisms. Aiming at the insufficient research on cyclic plasticity behavior of metals at microscale, the cyclic plastic deformation behavior and springback phenomenon of superalloy ultrathin sheets at diverse scales will be systematically explored and how different geometrical and grain size effects, crystal orientation as well as distribution affect the cyclic mechanical response will be also extensively clarified via multi-scaled cyclic shear test, micro-bending and finite element method. In addition, the microstructure evolution in cyclic plastic deformation will be studied, and the underlying deformation mechanism will thus be revealed. In addition, the validity of the frequently-used hardening models under cyclic deformation condition and micro scale will be verified. Based on the intrinsic mechanism of size effect and material microstructure evolution during the cyclic deformation, the multiscale cyclic constitutive model based on micro-mechanism will be established to accurately predict the springback at microscale. The project will thus enrich the understanding of the cyclic deformation behavior at micro scale with important theoretical significance, meanwhile, it has a broad prospect in engineering application for the precise springback compensation in microforming processes.