Grain size effect on near-threshold fatigue crack propagation in CrMnFeCoNi high-entropy alloy fabricated by spark plasma sintering
Grain size effect on near-threshold fatigue crack propagation in CrMnFeCoNi high-entropy alloy fabricated by spark plasma sintering
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DOI：
10.1016/j.engfracmech.2023.109317
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发表时间：
2023-05
影响因子：
5.4
通讯作者：
K. Fujita;Hayato Tsuboi;S. Kikuchi
中科院分区：
文献类型：
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作者：
K. Fujita;Hayato Tsuboi;S. Kikuchi
高熵合金(HEA)由五种或五种以上元素组成，具有等原子组成，具有优异的静态强度和延展性。研究了晶粒度对放电等离子烧结CrMnFeCoNi合金疲劳裂纹扩展的影响，该合金为面心立方结构的单相固溶体。在力比为0.1~0.8的情况下进行了应力强度因子K下降试验，在相对较低的力比下，细晶和粗晶组织的疲劳门槛值没有明显的差异。这一结果归因于粗晶内部的疲劳裂纹反射。即使是细晶试样，裂纹闭合程度也很高，超过了具有相同细晶的奥氏体不锈钢的闭合程度。因此，在目前的CrMnFeCoNi合金中，晶粒度对门槛应力强度因子范围的影响并不显著，与奥氏体不锈钢的行为相反。
High-entropy alloys (HEAs), which comprise five or more elements and have an equiatomic composition, are known to exhibit superior static strength and ductility. The present study evaluated the effect of grain size on fatigue crack propagation in a CrMnFeCoNi alloy comprising a single-phase solid solution with a face-centered-cubic structure and fabricated by spark plasma sintering. Stress intensity factor-Kdecreasing tests were conducted with force ratios from 0.1 to 0.8, and no noticeable differences in fatigue threshold were observed between specimens having fine-grained and coarse-grained structures at relatively low force ratios. This result was attributed to fatigue crack reflection inside coarse grains. The magnitude of crack closure was high even in the fine-grained specimens and exceeded that of austenitic stainless steel having the same fine grains. Thus, the effect of grain size on the threshold stress intensity factor range was not significant in the present CrMnFeCoNi alloy, in contrast to the behavior of austenitic stainless steels.