Comparison of the cyclic stress-strain behaviour of single-and 〈111〉 multiple-slip-oriented copper single crystals

Abstract The stress-strain behaviours of single- and multiple-slip-oriented copper single crystals were compared at a constant plastic strain amplitude in the plateau range of the cyclic stress-strain curve. The single slip orientation was 5° from [011] towards [ 1 12], and the multiple slip orientation [ 1 11]. The results obtained for single-slip-oriented crystals corresponded closely to those reported in earlier work and only minor differences could be seen. For multiple-slip-oriented crystals a strong initial hardening appeared from the beginning of fatigue cycling with a clear peak appearance subsequently; this was followed by a softening period which did not lead to any saturation value. Two distinct ranges, I and II, were observed as a function of the applied γ p 1 and these were respectively lower and higher than 0.1% for multiple-slip-oriented crystals. The energy parameter βE gave information about persistent slip band initiation in single-slip-oriented crystals but it seemed to be difficult to apply it to multiple-slip-oriented crystals because of the activity of many different slip systems.

[1]  J. Embury,et al.  The relation between surface and interior structures in low-amplitude fatigue , 1968 .

[2]  A. T. Winter,et al.  A model for the fatigue of copper at low plastic strain amplitudes , 1974 .

[3]  A. Abel.  Fatigue of copper single crystals at low constant plastic strain amplitudes , 1978 .

[4]  V. Kuokkala,et al.  The PSB structure in multiple-slip oriented copper single crystals , 1984 .

[5]  A. S. Cheng,et al.  The high cycle fatigue life of copper single crystals tested under plastic-strain-controlled conditions , 1981 .

[6]  P. J. Woods.  Low-amplitude fatigue of copper and copper-5 at. % aluminium single crystals , 1973 .

[7]  G. Kostorz,et al.  Voids produced by fatigue in copper single crystals of 〈111〉-orientation , 1981 .

[8]  R. Pascual,et al.  Low amplitude fatigue of copper single crystals—I. The role of the surface in fatigue failure , 1983 .

[9]  U. F. Kocks,et al.  Fatigue hardening and fatigue life , 1972 .

[10]  H. Mughrabi,et al.  The cyclic hardening and saturation behaviour of copper single crystals , 1978 .

[11]  A. Winter.  The effect of work-hardening on the low strain amplitude fatigue of copper crystals , 1975 .

[12]  C. Laird,et al.  Strain localization in cyclic deformation of copper single crystals , 1975 .

[13]  J. Grosskreutz,et al.  Mechanisms of fatigue hardening in copper single crystals , 1969 .

[14]  H. Mughrabi.  Plateaus in the cyclic stress-strain curves of single- and polycrystalline metals , 1979 .

[15]  A. S. Cheng,et al.  Mechanisms of fatigue hardening in copper single crystals: The effects of strain amplitude and orientation , 1981 .