Regeneration of fatigue properties by methods of surface cold-work hardening

摘要

The possibility of fatigue properties regeneration for light-alloy structural components was investigated by methods of surface plastic deformation (SPD). Investigations were carried out using aluminium alloy specimens subjected to different levels of preliminary fatigue loading ("damages"). These specimens were subsequently subjected to vibration-assisted shot peening, or to surface cold working with a roller, and then they were fatigue tested to failure on the same stress level as that applied during preliminary fatigue loading. The analysis of the obtained data showed that the surface cold-work hardening of preliminary "fatigue-damaged" specimens was quite effective. Durability of "damaged" specimens was not only completely restored, but also exceeded the initial number of cycles to failure of polished specimens by from 3 to 4 times. Even after expiry of 40% of initial durability of specimens (n_i =3 x 10~5 cycles) subsequent surface cold-work hardening resulted in an increase of residual durability by 3 times in comparison with the durability of polished specimens. On the basis of these investigations it is possible to assume that for the greatest increase of machine parts durability it is expedient to apply methods of SPD, both while manufacturing the parts and during their maintenance.