Characterization of the very early and very reduced fatigue crack growth in Al-alloys under very low loading conditions

极低载荷条件下铝合金中非常早期且非常减少的疲劳裂纹扩展的表征

基本信息

批准号：
256256999
负责人：
Professorin Dr. Angelika Brückner-Foit
金额：
--
依托单位：
Institut für Werkstoffwissenschaft
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/256256999?language=en
关键词：
Characterization very early reduced fatigue

项目摘要

Recent research activities reflect the growing interest in the technologically as well as scientifically relevant problem of the failure of metallic materials applied in structural parts subjected to load regimes well below the classical fatigue limit. Very high cycle fatigue (VHCF) investigations primarily focus on the identification of crack initiation mechanisms, since overall fatigue life is dominated by this phenomenon. However, the key issue of the project submitted is a characterization of the crack growth behavior at very low cyclic stress amplitudes since in practice products are seldom free from flaws or cracks initiated during manufacturing processes or misuse. Although the description of the fatigue crack growth behavior by means of LEFM is formally accepted, drastic discrepancies are expected, which are mainly due to the rather small and by the crystal plasticity influenced plastic zone and its interaction with microstructural features. The effective mechanisms and their influences on the fatigue crack growth will be quantitatively characterized and simulated in the project submitted. The scope of experimental and simulation methods based on the expertise of three workgroups are therefore consolidated with the aim to develop a model-based characterization of the very slow crack growth at very low stress amplitudes. The sum of the outcomes of each individual research focus and the synergistic effect of the cooperation shall result in a coherent understanding of the fatigue crack growth mechanisms relevant for a precipitation hardening and a strain hardening aluminum alloy (each in two different microstructural conditions) allowing a transfer of the insights gained into common engineering practice.

最近的研究活动反映了对技术以及科学相关的问题的兴趣日益增长的问题，即在经典疲劳极限范围以下的结构部件中应用的金属材料的失败。非常高的循环疲劳（VHCF）研究主要集中于裂纹起始机制的识别，因为总体疲劳寿命由这种现象主导。但是，提交的项目的关键问题是在非常低的周期性应力振幅下的裂纹生长行为的表征，因为在实践中，很少没有在制造过程中或滥用过程中启动的缺陷或裂缝。尽管通过LEFM对疲劳裂纹生长行为的描述被正式接受，但预计会产生巨大的差异，这主要是由于相当小，并且由于晶体可塑性影响了塑料区域及其与微结构特征的相互作用。在提交的项目中，将对有效的机制及其对疲劳裂纹生长的影响进行定量表征和模拟。因此，基于三个工作组的专业知识的实验和仿真方法的范围是合并的，目的是开发基于模型的表征非常缓慢的裂纹生长在非常低的应力振幅下。每个单独研究重点的结果和合作的协同作用的总和应导致对与降水量强化和应变硬化铝合金相关的疲劳裂纹生长机制的一致理解（每两种不同的显微结构条件），从而使洞察力转移到公共工程实践中。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Near-threshold crack extension mechanisms in an aluminum alloy studied by SEM and X-ray tomography

DOI：
10.1016/j.ijfatigue.2018.08.024
发表时间：
2019-02
期刊：
International Journal of Fatigue
影响因子：
6
作者：
M. Wicke;A. Brueckner-foit;T. Kirsten;M. Zimmermann;Fatih Buelbuel;H. Christ
通讯作者：
M. Wicke;A. Brueckner-foit;T. Kirsten;M. Zimmermann;Fatih Buelbuel;H. Christ

Influence of rolling texture on near-threshold crack extension behavior in aluminum alloy EN AW-6082

轧制织构对铝合金 EN AW-6082 近阈值裂纹扩展行为的影响