Study on the influence of sample size and roughness on fatigue performance of 7085 aluminum alloy
YUAN Ke
GAO Dong
YIN Mei
LU Tingting
ZHENG Liling
LÜ Yang
CUI Yue
ZHOU Fengluan
Abstract：The fatigue limit of 7085 aluminum alloy was tested by four-point bending fatigue test for samples of different sizes and roughness.The results show that the greater the thickness of the specimen,the greater the ultimate fatigue strength of the material.The higher the surface roughness of the sample,the lower the ultimate fatigue strength of the material.The stress analysis and calculation of the specimen show that the dangerous cross section occurs at the position where the indenter contacts the specimen,where the specimen is subjected to the combined action of bending normal stress and shear force.With the increase of the thickness of the specimen,the shear force on the specimen decreases,and the bending normal stress on the specimen increases under the same fatigue limit.And vice versa.The relation between the surface roughness and the radius of curvature of the sample is shown by establishing a simplified model,and then the relationship between the surface roughness and the fatigue ultimate strength of the material is obtained.
Keywords：7085 aluminium alloyFour-point bending testFatigue limitSample thicknessRoughness
Publication Date：2025-07-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：6( 80-85 )