Improved surface integrity in Inconel 718 using small diameter hammer peening tools
Year: 2025
Type: article
Abstract: Machine Hammer Peening (MHP) is an emergent treatment that induces high compressive Residual Stresses (RS) which can enhance the in-service performance of components. This paper studies the use of small diameter MHP tools to improve the Surface Integrity (SI) of the nickel-based alloy Inconel 718 used in critical aero-engine components. Complementarily, the relaxation of RS is analyzed by in-situ annealing tests at in-service temperature combined with X-ray diffraction measurement. For this purpose, age hardened Inconel 718 discs were turned as reference condition, and then a pneumatic MHP tool was used under different conditions: two tool diameters (4 mm and 12 mm), feed rates (2.5 m/min and 5.0 m/min) and stepover distances (0.07 mm and 0.35 mm). Subsequently, surface topography characterization, RS measurements, nanoindentation tests, and microstructural observations were conducted. The in-situ annealing tests were done in the X-ray diffractometer at 550 °C for exposure periods from 0 to 20 h. The results demonstrate that 4 mm diameter tools generate smooth surfaces and induce significant compressive RS within a 0.5 mm thick layer. Residual stresses are relaxed, but they remain compressive even after a long thermal exposure. The microstructure of the surface layer (<10–15 μm) was affected by the preceding turning operation, but importantly, MHP did not induce additional damage.
Source: Chinese Journal of Aeronautics
Institutions: University of Manchester, Mondragon Unibertsitatea
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,000
OpenAlex ID: W4409787046