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The effects of ion implantation on the fatigue behavior of metals

Thesis/Dissertation ·
OSTI ID:6074403
The effects of ion implanatation on the fatigue behavior of metals were investigated. High stacking fault energy FCC materials of aluminum and copper, low stacking fault energy FCC material of austenitic stainless steel and HCP material of titanium were ion implanted by boron or nitrogen at energies of 50 KeV to 3 MeV. The doses were from 10{sup 15} ions/cm{sup 2} to 10{sup 17} ions/cm{sup 2}. Flexural bending fatigue experiments were conducted on both the implanted and unimplanted specimens. After fatiguing the surface topography was examined by optical microscopy and SEM, and the microstructure of the surface layer was investigated by TEM. At relatively small amplitudes, close to the fatigue limit, the ion-implanted surface layer suppresses the formation of persistent slip bands (PSB's). At higher stress-amplitudes the implanted layer is penetrated by dislocation-channels which develop into the equivalent of PSB's. For constant fatigue testing parameters the density of PSB's decreased with increasing implant dose, but the intensity of slip in the few dislocation-channel PSB's was increased. Cracks nucleated at these slip bands and propagated along them. A composite model is presented to qualitatively analyze the effect of ion implantation on fatigue strength.
Research Organization:
Case Western Reserve Univ., Cleveland, OH (USA)
OSTI ID:
6074403
Country of Publication:
United States
Language:
English