Ultrahigh Current Density Nitrogen Ion Implantation--       Effects on the Microstructure and High Cycle Fatigue        Properties
{'Code': '07030000', 'Directorate': {'Abbreviation': 'ENG', 'LongName': 'Directorate For Engineering'}, 'Division': {'Abbreviation': 'CMMI', 'LongName': 'Div Of Civil, Mechanical, & Manufact Inn'}}
{'SignBlockName': 'George F. Keyser', 'PO_EMAI': None, 'PO_PHON': None}
One of the most promising modern processes for surface modification is          ion implantation.  In order to achieve low cost ion implantation, a             unique broad beam (10 cm.dia.) ultrahigh current density (up to 1500            Micro A/Square cm compared to conventional 6 Micro A/Square cm) ion             implanter has been developed at the Colorado State University.  The             Principal Investigator will study the effects of high current density           ion implantation.  High temperatures are reached at high current                densities, but the short implantation time produced no change in the            bulk (beneath implanted zone) hardness or bulk microstructure in blocks         of 1018 martensitic steel and many other alloys following high current          density ion implantation.  The PI will investigate the following                aspects of high current density ion implantation: a) Permissible                current densities for steels based on the time and temperature of               implantation and the alloy content of steels, b) Comparison of the hard         nitride phases formed due to nitrogen ion implantation in alpha-iron at         low and high current densities by electron metallography, and c)                Comparison of high cycle fatigue resistance of alpha-iron subjected to          conventional low current density (10 Micro A/Square cm) and the CSU             high current density (1500 Micro A/Square cm) nitrogen ion                      implantation.  The PI has observed a four fold increase in the range of         nitrogen ions at high current densities, resulting in a greater                 retardation of surface slip.  Slip retardation would delay crack                initiation in high cycle fatigue and increase fatigue life.
{'FirstName': 'Walajabad', 'LastName': 'Sampath', 'PI_MID_INIT': None, 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Walajabad Sampath', 'EmailAddress': 'walajabad.sampath@colostate.edu', 'NSF_ID': '000421961', 'StartDate': '07/01/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'Colorado State University', 'CityName': 'FORT COLLINS', 'ZipCode': '805212807', 'PhoneNumber': '9704916355', 'StreetAddress': '601 S HOWES ST', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'Colorado', 'StateCode': 'CO', 'CONGRESSDISTRICT': '02', 'CONGRESS_DISTRICT_ORG': 'CO02', 'ORG_UEI_NUM': 'LT9CXX8L19G1', 'ORG_LGL_BUS_NAME': 'COLORADO STATE UNIVERSITY', 'ORG_PRNT_UEI_NUM': None}
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[{'Code': '1441', 'Text': 'MECHANICS'}, {'Code': '1446', 'Text': 'MATERIALS'}]
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8700688.xml'}