Fretting fatigue crack initiation and propagation in Ti6Al4V sheets under tribocorrosive conditions of artificial seawater and physiological solutions

Zeeshan Anjum (1) , Masood Shah (1, 2) , Hassan Elahi (3) , Mushtaq Khan (4) , Mohammad Mujahid (5) , Shahab Khushnood (1) , Faisal Qayyum (6)

1 University of Engineering and Technology [Taxila]
2 ICA - Institut Clément Ader
3 Department of Mechanical & Aerospace Engineering
4 School of Mechanical and Manufacturing engineering, Islamabad
5 School of Chemical and Materials Engineering
6 Institute of Metal Forming

The interaction of mechanical components experiencing relative movements and cyclic loads in a corrosive environment is known as fretting corrosion or tribocorrosion. In the current work, the mechanism of crack initiation and propagation in dovetail slots of Ti6Al4V samples (in contact with carbide rods) under fretting corrosion conditions was investigated. A newly developed test rig installed on a universal testing machine was used to conduct tests at 20 Hz frequency under 5 and 7.5 kN fretting loads. Tests were conducted at room temperature in 3.5% NaCl and phosphate-buffered saline solutions. Crack propagation in all samples was examined by a metallurgical microscope, and the detailed analysis of fractured samples was carried out by a scanning electron microscope. In comparison to dry conditions, early crack initiation and faster crack propagation were observed in salt and physiological solution environments. Colored spots and large amounts of chlorine, sodium, and oxygen were found around cracks, and plastically deformed regions in the 3.5% NaCl environment provided the evidence of a corrosive attack. Large amounts of oxygen, phosphorous, chlorine, potassium, and sodium were detected in the phosphate-buffered saline environment.

Mots clés: Fretting fatigue; Titanium; Novel testing method; Microscopic analysis; Crack propagation rate; titanium; novel testing method; microscopic analysis; crack propagation rate

Domaines: Matériaux; Sciences de l'ingénieur [physics]

Zeeshan Anjum, Masood Shah, Hassan Elahi, Mushtaq Khan, Mohammad Mujahid, et al.. Fretting fatigue crack initiation and propagation in Ti6Al4V sheets under tribocorrosive conditions of artificial seawater and physiological solutions. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2020, 234 (12), pp.1526-1534. ⟨10.1177/1464420720946431⟩. ⟨hal-02919891⟩