Bilateral submerged abrasive waterjet peening improved high-temperature fatigue strength of titanium alloy thin-walled simplified blades

Abstract

Waterjet peening has exhibited excellent performance in improving the surface integrity and fatigue life of metal components. This paper proposes a novel and efficient thin-walled simplified-blade-surface full-coverage strengthening method, namely the bilateral submerged abrasive waterjet peening process (BSA-WJP), to improve the surface integrity and fatigue strength of simplified aeroengine blades. First, the surface integrity of simplified titanium alloy TA19 blades treated with BSA-WJP at different abrasive flow rates (100, 175, and 250 g/min) was investigated. The results revealed that the lowest surface roughness value of Ra = 0.329 μm was obtained. Compressive residual stress (CRS) layers of 111–128 μm with a maximum CRS of 738 MPa were introduced to the simplified blade surface. Plastic deformation layers of 15–32 μm were formed on the simplified blade surface after BSA-WJP treatment. The microstructure of the BSA-WJP-treated simplified blade was further examined using transmission electron microscopy. It was found that ultrafine grains with an average size of 107 nm and dense dislocations were induced on the topmost surface and subsurface. Finally, the high-cycle vibration fatigue performance of the simplified TA19 blade at 450 °C was verified. The result revealed that a 13.6 % increase in the high-temperature fatigue limit of the simplified TA19 blade was achieved after BSA-WJP treatment. The fracture morphology revealed that the considerable CRS, grain refinement layer, and optimized surface morphology played significant roles in inhibiting the initiation and propagation of cracks. This study provides an effective method for improving the fatigue strength of titanium alloy thin-walled blades and has promising engineering application prospects.