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张剑, 郝奇, 邢光辉, 乔吉超. La基非晶合金蠕变缺陷激活机制. 力学学报, 待出版. DOI: 10.6052/0459-1879-23-482
引用本文: 张剑, 郝奇, 邢光辉, 乔吉超. La基非晶合金蠕变缺陷激活机制. 力学学报, 待出版. DOI: 10.6052/0459-1879-23-482
Zhang Jian, Hao Qi, Xing Guanghui, Qiao Jichao. Defect activation mechanism of creep in La-based amorphous alloy. Chinese Journal of Theoretical and Applied Mechanics, in press. DOI: 10.6052/0459-1879-23-482
Citation: Zhang Jian, Hao Qi, Xing Guanghui, Qiao Jichao. Defect activation mechanism of creep in La-based amorphous alloy. Chinese Journal of Theoretical and Applied Mechanics, in press. DOI: 10.6052/0459-1879-23-482

La基非晶合金蠕变缺陷激活机制

DEFECT ACTIVATION MECHANISM OF CREEP IN LA-BASED AMORPHOUS ALLOY

  • 摘要: 作为潜在的结构以及功能材料,非晶合金的变形行为研究始终受到广泛关注. 非晶合金力学行为与其微观结构非均匀性之间的内禀性关联是固体力学和固体物理研究领域内的重要科学问题之一. 本文选取具有优异玻璃形成能力和力学性能的La62Cu12Ni12Al14非晶合金为模型体系, 探索非晶合金蠕变变形机理及其缺陷激活演化机制. 基于蠕变实验, 我们系统地研究了退火对模型合金体系蠕变行为的影响, 采用唯象扩展指数方程和弛豫时间谱分析, 着重探讨了非晶合金扩展指数、特征弛豫时间、弛豫时间强度分布随退火时间的演化规律, 获得了退火处理对非晶合金蠕变的影响机理. 基于准点缺陷理论框架推导力学响应本构方程, 可精确描述非晶合金蠕变变形演化过程, 通过微剪切畴的形成、扩展以及不可逆合并合理解释了弹性、滞弹性、塑性变形分量的演化机制. 本文从非晶合金高温拉伸蠕变实验出发, 我们厘清了热力耦合作用下非晶合金缺陷激活机制, 同时为进一步探究非晶合金结构非均匀性微观起源提供新思路.

     

    Abstract: As a potential structural and functional material, the study of deformation behavior in amorphous alloys has consistently attracted widespread attention. The intrinsic correlation between mechanical/physical properties and the microstructural heterogeneity of amorphous alloy is an important issue in the field of the solid mechanics and solid physics. In the current work, La62Cu12Ni12Al14 amorphous alloy was selected as the model alloy, benefitting from the glass forming ability (GFA) and unique mechanical properties. The current work mainly focused on the creep deformation behavior of the La-based amorphous alloy. In parallel, the evolution of the activation of defects during the creep process was probed. In the framework of the stretched exponential equation and relaxation time spectrum, evolution of stretch exponent, characteristic relaxation time, and the distribution of relaxation time intensity in amorphous alloys over physical aging time were specifically investigated in order to probe the physical aging below the glass transition temperature on the creep behavior. The constitutive equation based on the quasi-point defects theory can be used to describe the creep deformation of amorphous alloys. The formation, expansion, and irreversible merging of shear microdomains were employed to provide a rational explanation for the evolution patterns of elastic, viscoelastic, and plastic deformation components. On the basis of the tensile creep behavior of amorphous alloy, the evolution in defect activation within amorphous alloys has been clarified, simultaneously, the research sheds new light on further investigating the microscopic origins of structural heterogeneity in amorphous alloys.

     

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