Interplay between oxidation and wear behavior of the Ti-48Al-2Cr-2Nb-1B alloy
- Univ. di Trento (Italy). Dipt. di Ingegneria dei Materiali
This study deals with some aspects of the dry sliding behavior of a gamma TiAl-based alloy with the following composition: Ti-48Al-2Cr-2Nb-1B (at. pct). The tribological system consisted of an AISI M2 steel disk sliding against TiAl alloy sheets. Different alloy microstructures--duplex, equiaxed, and lamellar--were considered, in order to check for their possible effect on the wear behavior. At low loads, a mainly abrasive mechanism was inferred from the phases present in the debris collected at the end of each test. An additional contribution from oxidational phenomena was found at higher loads. In such conditions, the equiaxed samples displayed a slightly better wear resistance. A remarkable improvement in wear resistance was observed when the alloy specimens were tested without a preliminary removal of the surface layer which resulted from the heat treatments carried out to obtain different microstructures. Again, some differences were found in the wear behavior of alloys with different microstructures. Again, some differences were found in the wear behavior of alloys with different microstructures. In this case, though, the difference can rather be attributed to the different morphology of the surface layers. Better performances were observed in those samples, both duplex and equiaxed, in which a good mechanical matching between the alloy and the outer scale was accomplished, thanks to the presence of a hardened interdiffusion zone. An aspect which should be considered further is the tribological coupling of the as-treated alloys. Indeed, the elevated hardness and surface roughness of the coating yields a significant wear of the sliding counterface.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 691374
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 30, Issue 8; Other Information: PBD: Aug 1999
- Country of Publication:
- United States
- Language:
- English
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