Experimental investigation on damage evolution in pre-corroded aluminum alloy 7075-T7651 under fatigue loading

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:799

Article

Song, Haipeng^1,2  Liu, Changchun¹  Zhang, Hao³  Yang, Xudong¹  Chen, Yajun¹  Leen, Sean B.⁴ 

[1] Civil Aviat Univ China, Sino European Inst Aviat Engn, Tianjin, Peoples R China

[2] Jiangsu Prov Key Lab Aerosp Power Syst, Nanjing, Peoples R China

[3] Yangzhou Univ, Coll Mech Engn, Yangzhou, Jiangsu, Peoples R China

[4] NUI Galway, Mech Engn, Coll Engn & Informat, Galway, Ireland

关键词: Aluminum alloy;    Pre-corrosion;    Fatigue failure;    Damage evolution;    Digital image correlation;   

DOI  :  10.1016/j.msea.2020.140206

来源: Elsevier

【 摘 要 】

This paper experimentally investigates the fatigue damage evolution in pre-corroded aluminum alloy (AA) 7075-T7651 via digital image correlation (DIC) and scanning electron microscopy (SEM). Three stages of fatigue damage evolution including damage accumulation, macro-crack initiation and propagation are identified and described via the combined analysis of damage severity curves and strain maps. The micro-cracking characteristics in the dominant fracture regions are examined by fractography analysis. The experimental results show that localized corrosion penetrated in the 'L-S' or 'L-T' surfaces promotes fatigue crack initiation, affecting crack nucleation location, cracking path, and is accompanied with quasi-cleavage fracture. Damage evolution and failure progression differed temporally and spatially between specimens for the same loading conditions, due to the stochastic diversity of localized corrosion. Multiple corrosion-induced cracks were observed to initiate and evolve under different loading conditions: three typical failure modes, viz. single crack fracture, multi-crack competition and multi-crack parallel growth, were observed to depend on loading condition and relative location of macro-crack initiation.

【 授权许可】

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