Chungai Zou, Yun Jiang, Ming Yang, Qinkai Guan, Peng Chen, Jiangping Nie
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引用次数: 0
Abstract
The impact of the gradient nanostructures on the fatigue properties of aluminum alloys remains limited. The ultrasonic surface rolling process (USRP) was utilized in this study to generate the gradient nanostructure on the surface of 7075 aluminum alloy, and the high fatigue properties with the stress ratio R = – 1 were following tested. The findings indicated that the fatigue limits of 3- and 6-passes-treated samples were found to reach 225 MPa (125%) and 200 MPa (100%), respectively, surpassing those of untreated sample. The characterizations of scanning electron microscope (SEM), laser confocal scanning microscope (LCSM), and X-ray diffractometer (XRD) showed a positive correlation between the number of rolling passes and the enhancement of the gradient hardening layer and residual compressive stress, contributing to the improvement in fatigue limit. Meanwhile, the SEM analysis of the fracture indicated that the fatigue crack initiation site was altered as a result of surface modification, and the crack initiation point of the 3-passes-treated sample was located further from the surface. Additionally, finite-element simulation was employed to analyze the stress distribution across the cross-section, and the fatigue risk coefficient Rf was used to quantify the impact of residual stress distribution and surface hardening on the crack initiation site. The results demonstrated that USRP not only altered the surface condition of the aluminum alloy but also changed its stress distribution in the cross-section. The combined effect of the two controlled the crack initiation site and the fatigue life of the 7075 aluminum alloy.
期刊介绍:
Archives of Civil and Mechanical Engineering (ACME) publishes both theoretical and experimental original research articles which explore or exploit new ideas and techniques in three main areas: structural engineering, mechanics of materials and materials science.
The aim of the journal is to advance science related to structural engineering focusing on structures, machines and mechanical systems. The journal also promotes advancement in the area of mechanics of materials, by publishing most recent findings in elasticity, plasticity, rheology, fatigue and fracture mechanics.
The third area the journal is concentrating on is materials science, with emphasis on metals, composites, etc., their structures and properties as well as methods of evaluation.
In addition to research papers, the Editorial Board welcomes state-of-the-art reviews on specialized topics. All such articles have to be sent to the Editor-in-Chief before submission for pre-submission review process. Only articles approved by the Editor-in-Chief in pre-submission process can be submitted to the journal for further processing. Approval in pre-submission stage doesn''t guarantee acceptance for publication as all papers are subject to a regular referee procedure.