Fatigue Behaviour Of Shot Peened Tia16v4 In The Temperature Range 20 Deg.c < T < 450 Deg. C

Author:  Hanagarth, Vohringer, Macherauch
Source:  Conf Proc: ICSP-3, (p.477-484)
Doc ID:  1987029
Year of Publication:  1987
The (_ + B)-titanium alloy TiA16V4 is applied as rotor blade and disc material for compressor cascades of modern flight engines. These aircraft structures are exposed to fatigue loading at temperatures up to T = 450 Deg C. Therefore knowledge about fatigue behaviour, especially fatigue crack growth in this temperature range is important. The number of investigations concerning the fatigue crack growth characteristics of TiA16V4 at elevated temperatures are still very limited, with exception of temperatures around of 540 Deg C. These results indicate a pronounced environmental effect, particularly at low Delta K levels where time dependent effects such as oxidation would be expected to predominate. In tests conducted in vacuum there was no intrinsic temperature effect up to 350 Deg C. Other investigations show a significant increase in crack growth rates with increasing temperature (up to 320 Deg C), especially at low Delta K and high R values. In other tests, the material appeared at T = 290 Deg C slightly more resistant to crack growth than at room temperature. In the present paper, fatigue crack propagation behaviour at room temperature, T = 250 Deg C and T = 450 Deg C was investigated. Additionally the influence of shot peening on fatigue crack propagation as a function of temperature was examined because above T = 300 Deg C there is a significant relaxation of residual stresses by thermal and cyclic loading.

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