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

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5908207

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

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1. Oak Ridge National Lab., TN (United States)
2. Auburn Univ., AL (United States). Dept. of Materials Engineering

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 Lab., TN (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5908207
• Report Number(s): CONF-911111-19; ON: DE92005473
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
360106 -- Metals & Alloys-- Radiation Effects
665300 -- Interactions Between Beams & Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
BORON
CHROMIUM ALLOYS
CRACKS
CRYSTAL STRUCTURE
ELEMENTS
FATIGUE
HARDNESS
ION IMPLANTATION
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NITROGEN
NONMETALS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
SEMIMETALS