Impression creep behavior of Babbitt alloy SnSb8Cu4

Abstract

Abstract The creep behavior of the babbitt alloy SnSb8Cu4 was studied by impression under constant stress in the range of 15-30 MPa and at temperatures in the range of 333-393 K. OM, XRD, and SEM technologies were used to investigate the microstructural evolution of the material before and after creep. In conclusion, the stress exponent of SnSb8Cu4 in impression condition is 2.7. The creep activation energy is 46.7 kJ × mol-1, which reveals that the creep mechanism is based on dislocation glide controlled by dislocation pipe diffusion. With an increase in creep temperature and stress, the thermal vibration of the atom and atomic diffusion velocity increase. Moreover, Cu6Sn5 phase cannot effectively hinder dislocation glide and strengthen the material in a condition of high creep temperature and high stress, thus resulting in the decrease of creep resistance. After creep, the grains are elongated along the deformation flow direction both near the pressure punch edge and in the hemispherical zone beneath the pressure punch. The most severe deformation zone is near the pressure punch edge, whereas, no detectable deformation is found in other areas. It is concluded that impression creep is a localized phenomenon.