Effects of mechanical surface treatments on fatigue performance of extruded ZK60 alloy

The effects of shot peening (SP) and ball-burnishing (BB) as mechanical surface treatments on the high cycle fatigue (HCF) performance of the extruded high-strength magnesium alloy ZK60 were investigated. Various Almen intensities (0-0.33 mmA) and burnishing pressures (0-100 bar) were applied to reach optimum HCF performance of SP and BB conditions, respectively. SP and BB not only result in marked changes in the near surface microstructures but also in pronounced strengthening and in generation of residual compressive stresses in the near-surface regions. Both SP and BB lead to significant improvements in the fatigue life of the electropolished reference (EP) provided that suitable process parameters were applied. Utilizing optimum process parameters, the 107 cycles fatigue strength increased from 150 MPa (EP) over 175 MPa (SP) to 200 MPa (BB).