Laser alloying of aluminum alloy AA 6061 with Ni and Cr. Part II. The effect of laser alloying on the fretting wear resistance

The probability of encountering fretting in machines and engineering structures is extremely high, and it is well known that aluminum alloys have poor fretting wear resistance. In this investigation, the effect of laser surface alloying of Ni and Cr on the fretting resistance of 6061 aluminum alloys under unlubricated conditions was studied. The fretting wear performance of the laser-treated alloys was characterized by evaluating the wear volume loss, the coefficient of friction and fretting mechanisms. It was found that the fretting wear resistance of 6061 aluminum alloy was improved by a factor of three after laser alloying, while the coefficient of friction was decreased. The effects of fretting conditions such as load and amplitude on the fretting wear behavior were evaluated. The fretting wear mechanisms of both untreated and laser-treated specimens were adhesive, abrasive, oxidation and delamination wear. At the beginning of fretting cycles, adhesive and abrasive wear were the main wear mechanisms. During long-time running, delamination and oxidation were the main wear mechanisms for both laser-treated and untreated specimens.