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 s tructures 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 fr etting wear performance of the laser-treated alloys was characterized by evaluating the wear volume loss, the coefficient of friction and fr etting mechanisms. It was found that the fretting wear resistance of 6 061 aluminum alloy was improved by a factor of three after laser alloy ing, while the coefficient of friction was decreased. The effects of f retting conditions such as load and amplitude on the fretting wear beh avior were evaluated. The fretting wear mechanisms of both untreated a nd laser-treated specimens were adhesive, abrasive, oxidation and dela mination wear. At the beginning of fretting cycles, adhesive and abras ive wear were the main wear mechanisms. During long-time running, dela mination and oxidation were the main wear mechanisms for both laser-tr eated and untreated specimens. (C) 1998 Elsevier Science S.A.