Scholarlink

<p>This study investigated the effects of over-aging on the fatigue behavior of Al–7.3Zn–2.5Mg–1.5Cu alloy through high-cycle fatigue (HCF) and fatigue crack growth (FCG) tests. The artificial aging progress was categorized as under aging, peak aging, and over-aging. Microstructural analysis indicated that as over-aging processed, the matrix and grain boundary precipitates coarsened, and the precipitate-free zones (PFZs) widened. The over-aged alloy exhibited the highest fatigue strength of 275&#xa0;MPa after 10<sup>7</sup> cycles. To understand these mechanisms were clarified by analysing, the HCF behavior, separating it into fatigue crack initiation (FCI) and fatigue crack propagation (FCP). An Analysis based on the cyclic plastic zone model revealed that increases in the precipitate size and volume fraction reduced the FCG rate. Moreover, cross-slip activation due to larger precipitates reduced the degree of localized deformation in PFZs, delaying FCI. This study systematically distinguished and analysed the FCI and FCP behaviors resulting from over-aging treatment in Al–Zn–Mg–Cu alloys, providing a foundational understanding of alloy development in the field of HCF.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Influence of Over-Aged Microstructure on Fatigue Crack Initiation and Propagation in Al–Zn–Mg–Cu Alloys

  • 期刊论文

  • 发表日期：

    2026年3月17日

查看全文
  • Dong-Yun Lee,
  • Yong-You Kim,
  • Yoona Lee,
  • Moo-Young Seok,
  • Beom-Rak Hong,
  • Namhyun Kang,
  • Hyoung-Wook Kim,
  • Yong Hee Jo

摘要

This study investigated the effects of over-aging on the fatigue behavior of Al–7.3Zn–2.5Mg–1.5Cu alloy through high-cycle fatigue (HCF) and fatigue crack growth (FCG) tests. The artificial aging progress was categorized as under aging, peak aging, and over-aging. Microstructural analysis indicated that as over-aging processed, the matrix and grain boundary precipitates coarsened, and the precipitate-free zones (PFZs) widened. The over-aged alloy exhibited the highest fatigue strength of 275 MPa after 107 cycles. To understand these mechanisms were clarified by analysing, the HCF behavior, separating it into fatigue crack initiation (FCI) and fatigue crack propagation (FCP). An Analysis based on the cyclic plastic zone model revealed that increases in the precipitate size and volume fraction reduced the FCG rate. Moreover, cross-slip activation due to larger precipitates reduced the degree of localized deformation in PFZs, delaying FCI. This study systematically distinguished and analysed the FCI and FCP behaviors resulting from over-aging treatment in Al–Zn–Mg–Cu alloys, providing a foundational understanding of alloy development in the field of HCF.

Graphical Abstract