WEAR BEHAVIOUR COMPARISON AMONG DIFFERENT SURFACE TREATMENTS ON TI6AL4V ALLOY
Samples of the Ti6Al4V alloy were subjected to various surface treatments: nitrogen ion implantation, nitriding with two reactive gas atmospheres differing in composition and pressure, PVD - TiN coating and oxidation. A boronizing procedure failed to produce a continuous boride layer on the alloy. The surface layers were studied by X-ray diffraction analyses, optical scanning and, limited to implanted samples, transmission electron microscopy. Wear tracks were observed by SEM. The samples were subjected to dry wear tests with a pin on ring coupling, at 3.8 m/s sliding speed, 10, 20 and 40 N applied load, in laboratory air at room temperature. The antagonist material was a steel cylinder 40 mm in diameter, coated with a mixture of Al-2O-3 and TiO-2(13%). To evaluate the wear rate, the wear track depth was measured periodically. The PVD - TiN coated, thermochemically nitrided and oxidised samples all displayed a remarkable improvement in wear behaviour, as compared with untreated or N implanted samples. Mild wear regimes were observed, persisting up to sliding distances which varied depending on applied load and surface treatment. In each regime, wear rates were calculated by linear interpolations. In the mild wear regime, the lowest wear rates were found for Ti6Al4V samples nitrided at 800 degrees C for 1 h in pure low pressure nitrogen. The longest mild wear regime, however, was found for the alloy nitrided in argon with 1% N-2. Wear rates in different regimes, as well as mild to severe wear transitions, were evaluated and discussed with reference to the applied load, surface modifications induced by the various treatments and wear morphology.
Bibliographic Reference: EUROTRIB 1985, LYON (FRANCE), SEPT. 9-12, 1985 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 32303 ORA
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Record Number: 1989124021000 / Last updated on: 1987-01-01
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