The Microstructure Characterization of a Drive Shaft Spline from an Aero-Engine Fuel Pump During Fretting Wear

Abstract

To understand fretting wear caused by high-frequency vibrations, the microstructure of the worn surface and subsurface of a drive shaft spline from an aero-engine fuel pump is characterized and analyzed. The results show that there are adhesion, deformation, oxidation and crack on the worn surface of drive shaft spline. Plastic deformation induces dislocations multiplication that expand into subgrains and transform into equiaxed nanocrystals. Dislocations generated by these grains in the subsequent plastic deformation will be quickly absorbed by grain boundaries, which reduces the stress concentration caused by dislocation blocks and significantly delaying cracking. However, wear cracks tend to form at the interfaces of short rod-like nanocrystals near the worn surface and propagate along grain boundaries, accelerating the spalling of material. These results provide guidance for the design and use of drive shaft splines.

Keywords: Aero-engine, Drive shaft spline, 40CrNiMoA steel, Fretting wear, microstructure