Effect of natural aging by multifunction cavitation on plane bending fatigue behaviour of heat-treatable Al-Si7Mg aluminum alloys and its fatigue strength estimation

• Published in: International journal of fatigue Vol. 185; p. 108352
• Main Authors: Kikuchi, Shoichi, Matsuoka, Shunta, Yoshimura, Toshihiko, Ijiri, Masataka
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2024
• Subjects: Aging; Aluminum alloy; Fatigue strength estimation; Hardness; Multifunction cavitation; Residual stress; Aging; Fatigue strength estimation; Hardness; Multifunction cavitation; Residual stress; Aluminum alloy
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2024.108352

•MFC increased significantly the hardness of aluminum alloys without T6 treatment.•MFC generated compressive residual stress on the surface of aluminum alloys.•MFC improved the fatigue properties of aluminum alloys.•The fatigue strength of MFC-treated aluminum alloys showed same as T6 treated one.•The fatigue strength of MFC-treated aluminum alloys was estimated. The effect of natural aging by multifunction cavitation (MFC) on the fatigue behaviour of heat-treatable Al-Si7Mg aluminum alloys was examined. Surface observation and plane bending fatigue tests were conducted for the MFC-treated aluminum alloys at a stress ratio, R, of −1. The hardness of aluminum alloy without T6 treatment was significantly increased by MFC due to both the work hardening and natural aging. MFC treatment improved the fatigue lives and the fatigue strength at N = 107 cycles of aluminum alloys due to the generation of compressive residual stress and increasing the surface hardness; however, surface pits were large enough to easily nucleate an initial fatigue crack. In addition, the fatigue strength at N = 107 cycles of MFC-treated aluminum alloys can be estimated considering the residual stress, pit size and surface hardness.