Impurity effects on bonding charge in Ni{sub 3}Al

Conference · Tue May 14 04:00:00 EDT 1996

OSTI ID:253371

Sun, Sheng N; Kioussis, N; Lim, Say-Peng ^[1]; Gonis, A; Gourdin, W ^[2]

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1. California State Univ., Northridge, CA (United States). Dept. of Physics and Astronomy
2. Lawrence Livermore National Lab., CA (United States)

We have studied the effect of B and H on the charge density in Ni{sub 3}Al employing first-principles electronic structure calculations based on the FLMTO method. The changes in the electronic structure induced by B result from hybridization of d states of the nearest neighbor Ni atoms with adjacent B-{ital PP} states. Thus, boron prefers to occupy Ni-rich octahedral interstices [X(7)]. Boron greatly enhances the intraplanar metallic bonding between the Ni atoms, enhances the interplanar bonding between the NiAl layers in [001] direction, and reduces the bonding-charge directionality near the Ni(3) atoms. It is concluded that B acts to increase crystal cohesion. Hydrogen enhances the bonding-charge directionality near Ni(3) atoms and has virtually no interstitial charge enhancement, suggesting that H does not promote local cohesion. When both B and H are present, the dominant changes in the electronic structure induced by B and H seems to have little effect.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); Department of the Army, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 253371
• Report Number(s): UCRL-JC--123983; CONF-9506148--2; ON: DE96012185; CNN: Grant No. DAAH04-93-G-0427; Grant No. B157318
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
BORON ADDITIONS
ELECTRONIC STRUCTURE
HYDROGEN ADDITIONS
INTERATOMIC FORCES
INTERMETALLIC COMPOUNDS
NICKEL BASE ALLOYS