[Experimental studies of the structure, chemistry, and properties of grain boundaries]. [Annual report, June 1, 1993--May 31, 1994]
Observations have shown that the APB energy in boron-doped grain boundaries in Ni{sub 3}Al decreases with increasing misorientation angle. Boron segregation to a grain boundary in Ni{sub 3}Al has been observed for the first time using EELS. The boron distribution along a large angle grain boundary in Ni{sub 0.76}Al{sub 0.24} was shown to be not uniform. The boron-rich regions of the grain boundary were seen to have similar nickel bonding to bulk Ni{sub 3}Al. Undoped and boron-poor regions of the grain boundary have bonding similar to that in pure Ni (less filled Ni d bands) which suggests these Ni atoms have fewer Al nearest neighbors and weaker Ni-Al bonding than in bulk Ni{sub 3}Al. Finally, radiation damage was seen to occur in freshly prepared specimens at beam voltages as low as 100 kV but could be prevented by carbon coating the samples.
- Research Organization:
- Cornell Univ., Ithaca, NY (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-85ER45211
- OSTI ID:
- 10156695
- Report Number(s):
- DOE/ER/45211--23; ON: DE94012900; BR: KC0201010
- Country of Publication:
- United States
- Language:
- English
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