Probabilistic Risk of Titanium Disks Considering Residual Stresses of Hard Alpha Inclusions

Abstract

In aeroengine titanium alloy components, hard alpha (HA) inclusions strongly affect material performance, especially in terms of fatigue properties. Residual stresses caused by thermal expansion mismatch during the cooling process affect the fatigue life of metal components. This study proposes a method of probabilistic risk assessment for aeroengine disks considering the residual stresses of HA inclusions. Specifically, numerical procedures are adopted to investigate the residual stresses of an inclusion under surface effects, and a functional relationship model of residual stresses under surface effects is proposed. To deal with the randomness of inclusion size and position, a calculation criterion for the residual stresses of an inclusion is established. Analysis of an aeroengine compressor disk shows that the expected decline in the failure risk of the disk is approximately 27% under the consideration of residual stresses. The proposed method predicts the failure risk more accurately, and is thus valuable for the safety assessment of an aeroengine titanium disk.