ISSN:
1460-2695
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
In an attempt to understand the fatigue crack initiation and growth behavior of planar slip alloys, studies have been carried out in strain control on Cu-16 at.% A1 single crystals oriented for easy glide. Alloy single crystals of Cu-16 at.% A1 do not show saturation like copper crystals, but harden slowly and steadily throughout life, for the whole range of amplitudes applied. Cracks, the initiation and growth of which were studied by the sharp corner technique, were found to initiate when the peak stress reached 32 MPa irrespective of strain amplitude. The distribution of crack sizes in Cu-16 at.% A1 single crystals was found to be more skewed to small cracks than that of copper. This behavior is attributed to the frequent migration of the bands of localized slip in this material. The fatigue lives of this alloy at low strain amplitudes (ypm 〈 6-7 × 10−3) were found to be longer than those of copper single crystals because the strain is distributed more homogeneously than in copper. At high strain amplitudes, however, they become shorter because of the higher peak stress. The fatigue lives of Cu-A1 crystals are predicted from those of copper on the basis of the different volume fractions of localized strain in the two materials; the prediction agrees well with the actual lives of Cu-Al crystals. By geometrical consideration of secondary slip planes with respect to a primary crack, it was found that the critical system (A6) is most favored for secondary cracking adjacent to a primary crack.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1460-2695.1991.tb00650.x
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