Acta Metallurgica Sinica (English Letters) ›› 2016, Vol. 29 ›› Issue (8): 782-792.DOI: 10.1007/s40195-016-0449-3

• Orginal Article • Previous Articles    

A Comparison Study of Wear and Fretting Fatigue Behavior Between Cr-alloyed Layer and Cr-Ti Solid-solution Layer

Shou-Ming Yu(),Dao-Xin Liu(),Xiao-Hua Zhang,Cheng-Song Liu   

  1. School of Aeronautics, Institute of Corrosion and Protection, Northwestern Polytechnical University, Xi’an 710072, China
  • Received:2016-03-29 Online:2016-08-10 Published:2016-08-10

Abstract:

This work reported a comparison between the wear and fretting fatigue (FF) behaviors of a Cr-alloyed layer and a Cr-Ti solid-solution layer. The hardness and toughness of both layers were evaluated to support this comparison. The results showed that the Cr-alloyed layer had high surface hardness but poor toughness, while the Cr-Ti solid-solution layer had excellent toughness but low hardness. The FF properties of the modified Ti6Al4V alloy depended on the trade-off between two factors: wear resistance and fatigue resistance. Although the Cr-alloyed layer could effectively resist the wear in fretting areas, its poor toughness caused the fatigue resistance to drop sharply and hence led to a premature failure in FF test. Due to the relatively good fatigue resistance, the Cr-Ti solid-solution layer had slightly higher FF life than that of the Cr-alloyed layer; however, its low hardness resulted in severe wear in correspondence with the fretting area and thus a failure to improve the FF properties of Ti6Al4V alloy. When combined with shot peening post-treatment, the FF life of both layers increased by about three times compared to that of the Ti6Al4V alloy. A further study showed that the poor toughness or low hardness still exerted negative influence on combination-treated samples.

Key words: Titanium alloy, Plasma chromizing, Shot peening, Fretting fatigue, Wear