铜铝合金拉伸-疲劳性能定量关系研究

Fatigue properties are essential for the long-term security of engineering materials, and an effective fatigue property prediction model could be consider as the theoretical basis of efficient prediction and optimization of materials’ fatigue properties. However, for the lack of objective reflections of the deformation and damage mechanisms, present fatigue property prediction models generally have limitations on their application range. Therefore, in this project, the internal correlations of deformation and damage mechanisms are considered as the basis of model construction. Systematic investigations will be conducted with Cu-Al alloys with various compositions and microstructures: complete tendency of tensile and fatigue properties could be obtained through tensile and fatigue tests; the congruence of damage mechanisms as well as the difference of damage localization degrees between tensile and fatigue could be intensively analyzed through careful microscopic characterization; the combination of experimental data and mechanism analysis would help determine the key parameters and basic functions of the model, thus achieve a quantitative correlation between tensile and fatigue properties. Then the big data of various engineering materials’ mechanical properties would be substitute into the quantitative relationship for further inspection and development, and finally establish a new fatigue property prediction model, thus contributing to the efficient anti-fatigue optimization design of metallic materials.

疲劳性能是保障工程材料长期服役可靠性的关键指标，而完善的疲劳性能预测模型则是促进材料疲劳性能高效预测与优化的理论基础。然而，由于缺乏对形变损伤机制的客观反映，现有的疲劳性能预测模型适用范围上普遍存在一定的局限性。为此，本项目以形变损伤机制的内在关联性作为模型构建的基础，选取不同成分及组织状态的铜铝合金为研究对象，通过系统的拉伸与疲劳性能实验，获得全面的拉伸—疲劳性能数据及变化趋势；并通过拉伸与疲劳破坏前后铜铝合金的微观表征分析，深入研究拉伸与疲劳损伤基本机制的一致性与损伤局部化程度的差异性；继而结合数据规律与机制分析的结果，确定模型关键参数与基本函数形式，建立拉伸—疲劳性能之间的定量关系；进一步代入工程材料力学性能大数据，对定量关系加以检验与发展，最终形成完善的疲劳性能预测新模型，以助力金属材料的高效抗疲劳优化设计。

本项目通过对不同成分、不同组织状态下铜铝合金拉伸与高周疲劳性能及形变损伤微观机制的系统研究，构建了基于材料强度塑性制约关系的疲劳强度预测定量模型，进一步发展完善并投入应用。主要研究成果如下：1）发现在铜铝合金抗拉强度——疲劳强度关系中，普遍呈现先升后降的非线性关系，疲劳强度存在峰值。2）提出铜铝合金强度与塑性的相互制约是拉伸与疲劳非线性关系产生的内在机制。3）基于强塑制约基本关系，结合大量工程材料疲劳数据，建立了屈服强度（Y）、抗拉强度（T）及疲劳强度（F）三者间的定量关系，构建了Y-T-F模型框架。4）在Y-T-F关系基础上，建立了模型各个关键参数与材料成分、组织和缺陷三类影响因素间的定量关系，完善了材料疲劳强度预测功能并明确了材料抗疲劳设计方向。5）积极推进Y-T-F模型的工程应用，该模型已作为理论支持参与了中车长客“轨道车辆常用材料与焊接接头疲劳数据分析平台”、辽弹“板簧疲劳寿命预测系统”的建设，目前均已完成开发且运行良好，展现出广阔的应用前景。