Running-in performance of 7075 aluminum alloy strengthened by burnishing technology.

A 2D ultrasonic burnishing technology was employed to strengthen 7075 aluminum alloy. The running-in experiments for original and burnished samples were implemented, and the running-in performance was explored qualitatively and quantitatively. The results show that the worn surface of an original sample exhibited the peelings, scratches, and abrasive particles, yet the wear form of a burnished sample was relatively single, mainly with scratches. The quantitative parameter "maximum distance between phase points dmax" was calculated. During the friction and wear process, the dmax of friction coefficient signal displayed the variation of first decreasing and then stabilizing, which was consistent with the running-in and steady-state stages of the friction system. Compared with the original sample, the burnished sample had a less dmax, which indicated that the phase trajectory had a more convergence, and the friction system had a better stability. This study can guide surface strengthening and running-in performance analysis. [ABSTRACT FROM AUTHOR]