In transportation light metal matrix composites (L-MMCs) are used increasingly due to their improved creep resistance even at higher application temperatures. Therefore, the creep behavior and failure mechanisms of creep loaded particle reinforced L-MMCs have been investigated intensively. Until now, creep damage analyses are usually performed ex situ by means of interrupted creep experiments. However, ex situ methods do not provide sufficient information about the evolution of creep damage. Hence, in situ synchrotron X-ray 3D-µ-tomography investigations were carried out enabling time and space resolved studies of the damage mechanisms in particle-reinforced titanium- and aluminum-based metal matrix composites (MMCs) during creep. The 3D-data were visualized and existing models were applied, specifying the phenomenology of the damage in the early and late creep stages. During the early stages of creep, the damage is determined by surface diffusion in the matrix or reinforcement fracture, both evolving proportionally to the macroscopic creep curve. In the late creep stages the damage mechanisms are quite different: In the Al-MMC, the identified mechanisms persist proportional to creep strain. In contrast, in the titanium-MMC, a changeover to the mechanism of dislocation creep evolving super-proportionally to creep strain occurs.

中文翻译：

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蠕变条件下颗粒增强轻金属基复合材料的原位3D-μ层析成像

在运输中，轻金属基复合材料（L-MMCs）由于即使在较高的应用温度下也具有改善的抗蠕变性，因此越来越多地被使用。因此，已经对蠕变加载的颗粒增强L-MMC的蠕变行为和破坏机理进行了深入研究。到目前为止，蠕变损伤分析通常是通过中断的蠕变实验在异地进行的。但是，非原位方法不能提供有关蠕变损伤演变的足够信息。因此，进行了原位同步加速器X射线3D-μ断层扫描研究，从而实现了蠕变期间颗粒增强的钛和铝基金属基复合材料（MMC）的损伤机理的时空解析研究。可视化3D数据并应用现有模型，详细说明蠕变早期和晚期破坏的现象。在蠕变的早期阶段，损伤是由基体中的表面扩散或钢筋断裂引起的，两者均与宏观蠕变曲线成比例地演化。在蠕变后期，损伤机理是完全不同的：在Al-MMC中，确定的机理与蠕变应变成正比。相反，在钛-MMC中，发生了向位错蠕变机理的超比例转变为蠕变应变的转变。确定的机理与蠕变应变成比例。相反，在钛-MMC中，发生了位错蠕变的机理向蠕变应变的超比例演变。确定的机理与蠕变应变成比例。相反，在钛-MMC中，发生了向位错蠕变机理的超比例转变为蠕变应变的转变。