NSF Org:	DMR Division Of Materials Research
Recipient:	NORTHWESTERN UNIVERSITY
Initial Amendment Date:	February 22, 2001
Latest Amendment Date:	January 11, 2005
Award Number:	0095381
Award Instrument:	Continuing Grant
Program Manager:	Harsh Deep Chopra DMR  Division Of Materials Research MPS  Directorate for Mathematical and Physical Sciences
Start Date:	March 1, 2001
End Date:	February 28, 2006 (Estimated)
Total Intended Award Amount:	$306,771.00
Total Awarded Amount to Date:	$306,771.00
Funds Obligated to Date:	FY 2001 = $105,241.00 FY 2002 = $99,063.00 FY 2003 = $102,467.00
History of Investigator:	David Dunand (Principal Investigator) dunand@northwestern.edu Yip-Wah Chung (Former Principal Investigator)
Recipient Sponsored Research Office:	Northwestern University 633 CLARK ST EVANSTON IL  US  60208-0001 (312)503-7955
Sponsor Congressional District:	09
Primary Place of Performance:	Northwestern University 633 CLARK ST EVANSTON IL  US  60208-0001
Primary Place of Performance Congressional District:	09
Unique Entity Identifier (UEI):	EXZVPWZBLUE8
Parent UEI:
NSF Program(s):	METAL & METALLIC NANOSTRUCTURE
Primary Program Source:	01000102DB NSF RESEARCH & RELATED ACTIVIT app-0102  app-0103
Program Reference Code(s):	9161, AMPP
Program Element Code(s):	177100
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.049

ABSTRACT

0095381
Chung

This grant deals with the fundamental issues surrounding the moisture-induced embrittlement of intermetallic alloys with a focus on (Ni,Fe)Ti. In spite of the reactivity of individual components to water, (Ni,Fe)Ti alloys are not embrittled by moisture, as long as the Fe concentration is less than 9 a/o. However, they become severely embrittled by moisture at higher Fe concentrations. This calls for a detailed re-examination of the traditionally accepted mechanism of moisture-induced embrittlement of intermetallics. That is, in addition to the dissociation of water to produce atomic hydrogen on intermetallic surfaces, what other factors are required to produce moisture-induced embrittlement? Using a surface science approach, this study looks at the water vapor reactivity of single crystal (Ni,Fe)Ti surfaces of different orientations and Fe concentrations. The objective is to determine whether or not water dissociation to produce atomic hydrogen occurs, and, if so, how strongly the atomic hydrogen is bound to the intermetallic surface. Most important to improved understanding is a quantitative determination of the diffusivity of hydrogen on these surfaces using electron-stimulated desorption. These investigations should provide the necessary atomic scale details to explain the inter-relationships among moisture-induced embrittlement, surface reactivity, and mobility of atomic hydrogen in intermetallic alloys.
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Intermetallic alloys offer promise as high temperature structural metal alloys. One potential problem is the reactivity of intermetallics with the environment. This grant explores one facet of this problem.
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