Tensile and very high cycle fatigue behaviors of a compressor blade titanium alloy at room and high temperatures

Tensile and fatigue behaviors of a compressor blade titanium alloy TC17 at room and high temperatures (RT and HT) have been investigated up to very high cycle fatigue (VHCF) regime. Compared to RT, the HT tensile strength of TC17 titanium alloy decreases, but the elongation remains basically unchanged at HT. The fatigue S?N curves are changed from single linear mode at RT to bilinear mode at HT owing to the temperature effect, and the failure mode is transformed from the surface and subsurface crack initiations at RT to the surface crack initiation at HT. The brittle oxygen-enriched subsurface (BOES) layer on the specimen surface is responsible for the crack initiation at HT. The failure models of oxide shedding and oxide intrusion are proposed. Dislocation distribution indicates that the fatigue failure at HT is insensitive to the intrinsic material microstructure and is only related to the BOES layer on the specimen surface in the VHCF regime.

Automated summary

The tensile and fatigue behaviors of TC17 titanium alloy at room temperature and high temperature were studied, where it was found that the tensile strength decreases at high temperature while the elongation remains unchanged. The fatigue S-N curves and failure mode also change with temperature, with the crack initiation mainly attributed to the brittle oxygen-enriched subsurface (BOES) layer at high temperatures.