Study on the surface defect of aluminum alloy hole burnishing

The surface finish of holes plays a crucial role in their fatigue life, which is significantly compromised by the surface defect (SD) that appears during the burnishing process. In this paper, a kinematic model for hole burnishing was developed to study the formation mechanism of the SD, proposing the existence of the critical burnishing depth (BD) value. Hole burnishing experiments were conducted on aluminum alloy 7050, and the critical BD value was found to be approximately 0.14 mm, validating its existence. When the BD was less than the critical value, the burnished surface was smooth, and the fatigue life increased. When the BD exceeded the critical value, the SD appeared, and the fatigue life decreased. [Display omitted] •Model of the critical value of the burnishing depth in hole burnishing was proposed.•Sliding mechanism due to the insufficient friction in the hole burnishing was revealed.•Relationship between the critical value of the burnishing depth and the surface defect was established.