Multiple ion implantation effects on hardness and fatigue properties of Fe-13Cr-15Ni alloys

Conference · Sun Nov 17 00:00:00 EST 1991 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/0022-3115(92)90572-3· OSTI ID:10114282

Rao, G. R. ^[1]; Lee, E. H. ^[2]; Boatner, L. A. ^[2]; Chin, B. A. ^[3]; Mansur, L. K. ^[2]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Auburn Univ., AL (United States)
2. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
3. Auburn Univ., AL (United States)

Eight complex alloys based on the composition Fe-13Cr-15Ni-2Mo-2Mn-0.2Ti-0.8Si-0.06C were implanted simultaneously with 400 keV boron and 550 keV nitrogen, and investigated for microhardness changes and bending fatigue life. The dual implantation was found to decrease the fatigue life of all eight alloys although the implantation increased near-surface hardness of all eight alloys. This result was in contrast to the significant improvements found in the fatigue life of four B, N implanted simple Fe-13Cr-15Ni alloys. It was determined that the implantation suppressed surface slip-band formation, the usual crack initiation site, but in the complex alloys, this suppression promoted a shift to grain boundary cracking. A similar phenomenon was also observed when the simple Fe-13Cr-15Ni alloys were simultaneously implanted with boron, nitrogen and carbon wherein fatigue life decreased, and again, grain boundary cracks were observed. To test the hypothesis that ion implantation made the overall surface more fatigue-resistant but led to a shift to grain-boundary cracking, single crystal specimens of the ternary Fe-15Cr-15Ni were also implanted with boron and nitrogen ions. The fatigue life decreased for the single-crystal specimens also, due to concentration of applied stress along fewer slip bands as compared to the control single crystal specimens where applied stress was relieved by slip band formation over the entire gauge region. Fatigue life improvement by ion implantation at intermediate strain levels has a sensitive dependence on grain size as well as extent of slip band suppression.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10114282
• Report Number(s): CONF-911111--19; ON: DE92005473
• Resource Type: Conference paper/presentation
• Conference Information: Journal Name: Journal of Nuclear Materials Journal Issue: B Journal Volume: 191-194
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103
360106
665300
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BORON
CHROMIUM ALLOYS
CRACKS
CRYSTAL STRUCTURE
FATIGUE
HARDNESS
INTERACTIONS BETWEEN BEAMS AND CONDENSED MATTER
ION IMPLANTATION
IRON BASE ALLOYS
MANGANESE ALLOYS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NITROGEN
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS