Improving Surface Integrity of Aeroengine Blades Using Ultrasonic Surface Rolling Processing

The use of ultrasonic surface rolling processing (USRP) in the machining of aeroengine blades remains in the exploratory stage, as the application of high contact pressure during USRP leads to substantial deformation, which has a detrimental impact on the aerodynamic performance of the blades. This study aims to address the deformation issue through two strategies for optimizing blades made from titanium alloy. Firstly, profiling pads are employed to effectively mitigate blade deformation during the machining process. Secondly, a comprehensive exploration of different USRP treatment parameters-such as pressure, indentation depth, spacing, and processing time-is conducted to investigate their effects on the surface morphology, hardness, and residual stress of aeroengine blades to ensure that they meet the specific deformation requirements for aeroengine components. The evolution of microstructure induced by USRP treatment of the blades is also examined. The experimental findings reveal significant improvements following USRP treatment, including a substantial reduction in surface roughness (from 2.6 to 0.2 mu m), a significant enhancement in hardness (from 320 to 410 Hv), a refinement of surface grains, and the introduction of more favorable residual compressive stresses (about - 1000 MPa). These effects play an important role in improving the performance of aeroengine blades.