Strong correlation between crack initiation and high cycle fatigue behavior of Ti6Al4V ELI alloy with bimodal microstructure

IF 3.5 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Science Pub Date : 2025-04-23 DOI:10.1007/s10853-025-10867-w

Xiaohui Shi, Zirui Chen, Yuqi Qiao, Zhen Jing, Junwei Qiao

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引用次数: 0

Abstract

Crack initiation process could account for the main proportion of fatigue life. In this study, high cycle fatigue behavior of Ti6Al4V ELI alloy with bimodal microstructure was studied and its correlation with crack initiation was investigated. The results show that fatigue crack mainly initiated at subsurface or interior of the tested specimens. Fatigue life generally increases with increasing crack initiation site-specimen surface distance under same/similar stress level. The maximum stress level shows big influence on the locations of crack initiation sites. Higher maximum stress could lead the crack initiation site to an inner position within fatigue specimen, which can be attributed to the strengthening of necking effect. Based on analyses, the influence of maximum stress on the probability of different crack initiation modes was summarized. By comparing the calculation results, the fatigue specimens with interior crack initiation mode have obviously higher threshold stress intensity factor range than other modes, which indicates higher resistance to fatigue crack propagation. Besides, it was found that the fracture surface morphology of fatigue specimens contains three features, including initiation facet, propagation facet, and rough surface with tear ridges. Initiation facets occur most possibly due to the fracture of α_p grain and are always along (0001) plane as well as the biggest shear stress plane.

Graphical Abstract

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双峰组织Ti6Al4V ELI合金的裂纹萌生与高周疲劳行为有很强的相关性

裂纹萌生过程是影响疲劳寿命的主要因素。研究了具有双峰组织的Ti6Al4V ELI合金的高周疲劳行为，并探讨了其与裂纹萌生的关系。结果表明，疲劳裂纹主要发生在试件的表面下或内部。在相同或相似的应力水平下，随着裂纹萌生部位-试样表面距离的增加，疲劳寿命普遍增加。最大应力水平对裂纹起裂部位的位置影响较大。较高的最大应力可使裂纹起裂点向疲劳试样内部靠近，这可归因于颈缩效应的增强。在此基础上，总结了最大应力对不同裂纹萌生模式概率的影响。通过计算结果对比，内裂纹萌生模式的疲劳试样具有明显高于其他模式的阈值应力强度因子范围，表明其具有更高的抗疲劳裂纹扩展能力。疲劳试样的断口形貌包含起裂面、扩展面和带撕裂脊的粗糙面三个特征。起裂面主要由αp晶粒断裂引起，并沿（0001）面和最大剪应力面形成。图形抽象

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Materials Science 工程技术-材料科学：综合

CiteScore

7.90

自引率

4.40%

发文量

1297

审稿时长

2.4 months

期刊介绍： The Journal of Materials Science publishes reviews, full-length papers, and short Communications recording original research results on, or techniques for studying the relationship between structure, properties, and uses of materials. The subjects are seen from international and interdisciplinary perspectives covering areas including metals, ceramics, glasses, polymers, electrical materials, composite materials, fibers, nanostructured materials, nanocomposites, and biological and biomedical materials. The Journal of Materials Science is now firmly established as the leading source of primary communication for scientists investigating the structure and properties of all engineering materials.