EI、Scopus 收录
中文核心期刊
郝奇, 乔吉超. 基于微观结构非均匀性演化的非晶合金应力松弛动力学. 力学学报, 2022, 54(11): 3058-3067. DOI: 10.6052/0459-1879-22-255
引用本文: 郝奇, 乔吉超. 基于微观结构非均匀性演化的非晶合金应力松弛动力学. 力学学报, 2022, 54(11): 3058-3067. DOI: 10.6052/0459-1879-22-255
Hao Qi, Qiao Jichao. Stress relaxation dynamics for amorphous alloys based on the evolution of microstructural heterogeneity. Chinese Journal of Theoretical and Applied Mechanics, 2022, 54(11): 3058-3067. DOI: 10.6052/0459-1879-22-255
Citation: Hao Qi, Qiao Jichao. Stress relaxation dynamics for amorphous alloys based on the evolution of microstructural heterogeneity. Chinese Journal of Theoretical and Applied Mechanics, 2022, 54(11): 3058-3067. DOI: 10.6052/0459-1879-22-255

基于微观结构非均匀性演化的非晶合金应力松弛动力学

STRESS RELAXATION DYNAMICS FOR AMORPHOUS ALLOYS BASED ON THE EVOLUTION OF MICROSTRUCTURAL HETEROGENEITY

  • 摘要: 本文研究了Zr48(Cu5/6Ag1/6)44Al8 非晶合金应力松弛行为与固有微观结构非均匀性之间的关联. 非晶合金是典型非平衡固体, 其应力松弛过程伴随着老化效应, 本文首次考虑了经典KWW方程最可几特征时间\tau 和扩展指数\beta 在应力松弛过程中的耦合演化, 这表明探究应力松弛过程中应力松弛响应必须考虑结构状态的时间依赖性. 基于所研究非平衡状态非晶合金结构状态的演化, 厘清了非晶合金应力松弛行为中老化效应. 研究结果表明, 非晶合金应力松弛行为具有典型非指数特征, 单一特征时间的指数弛豫形式与有限特征时间的有限谱方法均无法合理描述非晶合金应力松弛实验, 这是由于非晶合金微观结构非均匀性所导致的特征时间谱连续分布. 此外, 非晶合金的名义弹性区域应力松弛行为与初始应变无关, 这主要是因为非晶合金应力松弛行为的流变本质, 即弹性和滞弹性可逆性变形随时间推移逐渐转化为黏塑性不可逆变形. 最后, 考虑了老化效应引起的结构参量演化以及进一步导致的变形行为改变, 应力松弛特征时间随时间逐渐增加, 扩展指数随时间逐渐减小.

     

    Abstract: The correlation between stress relaxation behavior and the evolution of microstructural heterogeneity of Zr-based amorphous alloys was probed. Amorphous alloy is the typical non-equilibrium solid system. Stress relaxation process is accompanied by aging effect of the amorphous alloy. In the current work, the coupling evolution of the most probably characteristic time \tau and stretched exponent \;\beta in the classical stretched function is considered for the first time, indicating the time dependence of structural state in the stress relaxation process. Based on the evolution of the non-equilibrium structure state of the amorphous alloys, the aging effect in the stress relaxation behavior was clarified. The results demonstrated that the stress relaxation behavior of amorphous alloys has non exponential characteristics. The exponential relaxation form of single characteristic time and the finite spectrum method of finite characteristic time cannot describe accurately the experimental results. This phenomenon is ascribed to the continuous distribution of the characteristic time spectrum caused by the microstructural heterogeneity of amorphous alloys. In addition, the stress relaxation behavior in the apparent elastic region is independent of the initial strain, which is due to the macroscopic flow nature of the stress relaxation behavior. Elastic and anelastic reversible deformation is transformed into viscoplastic (irreversible) deformation. Finally, Evolution of structural parameters caused by aging during stress relaxation is considered, which is reflected in the increase of characteristic time \tau and the decrease of stretched exponent \;\beta .

     

/

返回文章
返回