Fretting of CoCrMo and Ti6Al4V alloys in modular prostheses |
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| Authors: | A Oladokun M Pettersson M Bryant H Engqvist C Persson R Hall |
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| Affiliation: | 1. Institute of Functional Surfaces iFS, School of Mechanical Engineering, University of Leeds, Leeds, UKmn10a2o@leeds.ac.uk;3. Applied Materials Science, The ?ngstr?m Laboratory, Uppsala University, Uppsala, Sweden;4. Institute of Functional Surfaces iFS, School of Mechanical Engineering, University of Leeds, Leeds, UK |
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| Abstract: | Implantation of a total hip replacements (THR) is an effective intervention in the management of arthritis. Modularity at the taper junction of THR was introduced in order to improve the ease with which the surgeon could modify the length of the taper section and the overall length of the replacement. Cobalt chromium (Co–28Cr–6Mo) and titanium (Ti–6Al–4V) alloys are the most commonly used materials for the device. This study investigates the fretting behaviour of both CoCr–CoCr and CoCr–Ti couplings and analyses their damage mechanisms. A reciprocating tribometer ball on plate fretting contact was instrumented with in situ electrochemistry to characterise the damage inflicted by tribocorrosion on the two couplings. Fretting displacements amplitudes of 10, 25 and 50?μm at an initial contact pressure of 1?GPa were assessed. The results reveal larger metallic volume loss from the CoCr–CoCr alloy compared to the CoCr–Ti alloy, and the open circuit potential indicates a depassivation of the protective oxide layer at displacement amplitudes >25?μm. In conclusion, the damage mechanisms of CoCr–CoCr and CoCr–Ti fretting contacts were identified to be wear and fatigue dominated mechanisms respectively. |
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| Keywords: | Fretting Corrosion Orthopaedics CoCr Ti6Al4V Taper junction Modularity |
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