Physical Property, Fatigue
Plastic Strain Amplitude Dependence of Cyclic Deformation Behavior in Ultrafine Grained Cu Alloys Containing Fe Precipitates
2020 Volume 59 Issue 1 Pages 233-237
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2020 Volume 59 Issue 1 Pages 233-237
Cyclic softening is typical deformation behavior of ultrafine grained （UFG） metals fabricated by severe plastic deformation process such as ECAP （Equal channel angular pressing）. The softening is occurred with the formation of shear bands and the dynamic grain coarsening. In this study, the plastic strain amplitude dependence of cyclic deformation behavior of UFG Cu alloys containing Fe precipitates was investigated to understand the effect of the Zener pinning force to fatigue properties. Specimens of an UFG Cu–Fe alloy were made by the ECAP after aging treatment at 923 K for 95min. Fully–reversed tension–compression tests were carried out under constant plastic strain amplitudes of εpl＝2×10−4, 1×10−3, 2×10−3 at room temperature. The cyclic softening occurred in all conditions during fatigue tests. These cyclic softening curves were consisted of the rapid softening region and the steady softening region. There was a linear relationship between the softening rates calculated from the steady softening region and the plastic strain amplitudes. The softening rates of UFG Cu–Fe specimens were lower than that of the UFG Cu specimen.
