The dual role of martensitic transformation in fatigue crack growth.
The dual role of martensitic transformation in fatigue crack growth.
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DOI：
10.1073/pnas.2110139119
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发表时间：
2022-03-01
影响因子：
11.1
通讯作者：
Raabe D
中科院分区：
文献类型：
--
作者：
Wang X;Liu C;Sun B;Ponge D;Jiang C;Raabe D
大约90%的机械服务故障是由疲劳引起的。避免疲劳失效需要解决有关循环载荷下的微机械损伤过程的广泛知识缺口，这可能与静态载荷下的损伤过程有根本的不同。这对于变形诱发马氏体相变（DIMT）尤其如此，DIMT是合金最常见的强化机制之一。在这里，我们确定了两个拮抗机制介导的马氏体相变在疲劳过程中，通过原位观察，并证明了DIMT在疲劳裂纹扩展和其强大的裂纹尺寸依赖性的双重作用。我们的研究结果开辟了途径，设计耐疲劳合金，通过最佳使用的DIMT。它们还能够开发具有更高保真度的基于物理的寿命预测模型。形变诱发马氏体相变（DIMT）已被用于设计高性能合金，以防止静态载荷下的结构失效。然而，它对疲劳的有效性尚不清楚。这限制了DIMT在承受可变载荷的零件中的应用，尽管此类情况是结构失效的常见情况而不是例外。在这里，我们揭示了DIMT在疲劳裂纹扩展的双重作用，通过原位观察。DIMT介导的两种对抗性疲劳机制，即转化介导的裂纹止裂，防止裂纹扩展，和转化介导的裂纹聚结，促进裂纹扩展。这两种机制都是由于马氏体作为相变产物的硬度和脆性，而不是由于实际的相变过程本身。在疲劳裂纹扩展中，一种机制的流行程度主要取决于裂纹尺寸和母奥氏体相的机械稳定性。阐明这两种机制及其相互作用，允许微观结构设计和安全使用的亚稳合金，经历疲劳载荷。研究结果还揭示了亚稳合金的微观结构必须如何设计才能使材料具有耐疲劳性。
About 90% of all mechanical service failures are caused by fatigue. Avoiding fatigue failure requires addressing the wide knowledge gap regarding the micromechanical processes governing damage under cyclic loading, which may be fundamentally different from that under static loading. This is particularly true for deformation-induced martensitic transformation (DIMT), one of the most common strengthening mechanisms for alloys. Here, we identify two antagonistic mechanisms mediated by martensitic transformation during the fatigue process through in situ observations and demonstrate the dual role of DIMT in fatigue crack growth and its strong crack-size dependence. Our findings open up avenues for designing fatigue-resistant alloys through optimal use of DIMT. They also enable the development of physically based lifetime prediction models with higher fidelity. Deformation-induced martensitic transformation (DIMT) has been used for designing high-performance alloys to prevent structural failure under static loads. Its effectiveness against fatigue, however, is unclear. This limits the application of DIMT for parts that are exposed to variable loads, although such scenarios are the rule and not the exception for structural failure. Here we reveal the dual role of DIMT in fatigue crack growth through in situ observations. Two antagonistic fatigue mechanisms mediated by DIMT are identified, namely, transformation-mediated crack arresting, which prevents crack growth, and transformation-mediated crack coalescence, which promotes crack growth. Both mechanisms are due to the hardness and brittleness of martensite as a transformation product, rather than to the actual transformation process itself. In fatigue crack growth, the prevalence of one mechanism over the other critically depends on the crack size and the mechanical stability of the parent austenite phase. Elucidating the two mechanisms and their interplay allows for the microstructure design and safe use of metastable alloys that experience fatigue loads. The findings also generally reveal how metastable alloy microstructures must be designed for materials to be fatigue-resistant.
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DOI：
10.1007/bf02672301
发表时间：
1975-01-01
期刊：
METALLURGICAL TRANSACTIONS
影响因子：
--
作者：
OLSON, GB;COHEN, M
通讯作者：
COHEN, M
DOI：
10.1016/0001-6160(78)90211-0
发表时间：
1978-01-01
期刊：
ACTA METALLURGICA
影响因子：
--
作者：
HORNBOGEN, E
通讯作者：
HORNBOGEN, E
影响因子：
9.4
作者：
Ju, Yun-Byum;Koyama, Motomichi;Noguchi, Hiroshi
通讯作者：
Noguchi, Hiroshi
影响因子：
64.8
作者：
Li, Zhiming;Pradeep, Konda Gokuldoss;Tasan, Cemal Cem
通讯作者：
Tasan, Cemal Cem
影响因子：
6
作者：
Murakami, Yukitaka
通讯作者：
Murakami, Yukitaka