Fretting wear evolution of γ-TiAl alloy

Abstract

Fretting wear evolution of γ-TiAl alloy was investigated. Evolution of wear scar, tribolayer and wear debris were studied using optical microscope and scanning electron microscope. The results show that the wear debris generated from γ-TiAl alloy can be compacted to form a tribolayer rapidly after 100 fretting cycles. At the starting stage, the rapid formation and rupture of tribolayer alternatively occur due to insufficient thickness of the tribolayer. With the proceeding of fretting, the thickness of tribolayer increases due to increase in the amount of the wear debris, which makes the tribolayer more stable. The evolution of the wear debris and the formation of tribolayer significantly influence the fretting wear behavior of γ-TiAl alloy. The wear rate of γ-TiAl alloy decreases rapidly from 255.6 × 10−3μm3 /(N·μm) after 2000 fretting cycles to 35.5 × 10−3μm3 /(N·μm) after 10,000 fretting cycles when a thick tribolayer is formed. A physical model was proposed to describe the evolution process of the fretting wear of γ-TiAl alloy.