Damping behavior of typical titanium alloys by varied frequency micro harmonic vibration at cryogenic temperatures

In this paper, micro harmonic vibration was applied to the typical titanium alloys to clarify their damping performance at cryogenic temperatures. The effects of vibration modulus at different frequencies were elaborately analyzed, and the crack propagation mechanism was discussed. The increase of internal dislocations improves the damping performance and eventually leads to interface cracking, which is positively correlated with frequency. More importantly, dislocations of b phase aggregated at the interface, leading to interface cracks and transgranular fractures by stress concentration. Whereas, dislocations in the a phase are first activated and then glide toward the boundary to cause cracking, resulting in intergranular fracture. During harmonic vibration at 0 similar to-60 degrees C with 200 Hz, the crack propagation of a phase always has a hysteresis behavior compared with that of b phase. When Delta K = 0.137 MPa m(1/2) (-60 degrees C, 200 Hz), the second crack tip of beta phase is deflected in different directions, leading to higher harmonic vibration energy is consumption. As a result, the crack growth rate slows down and the damping performance reaches its peak. This contribution is expected to provide experimental data and theoretical support for the vibration damping behavior of typical titanium alloys at cryogenic temperature. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This paper investigates the damping performance of typical titanium alloys at cryogenic temperatures using micro harmonic vibration. The effects of vibration modulus at different frequencies are analyzed, and the crack propagation mechanism is discussed. The increase of internal dislocations improves damping performance and leads to interface cracking, which is correlated with frequency. The aggregation of dislocations at the interface causes interface cracks and transgranular fractures in the b phase, while dislocations in the a phase activate and glide toward the boundary, resulting in intergranular fractures. The crack propagation of the a phase exhibits hysteresis behavior compared to the b phase during harmonic vibration. At -60°C with 200 Hz, the deflected second crack tip of the beta phase consumes higher harmonic vibration energy, slowing down the crack growth rate and reaching peak damping performance. The study provides experimental data and theoretical support for the vibration damping behavior of typical titanium alloys at cryogenic temperature.