Precipitation of Kr in Ni at room temperature

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6905521

Birtcher, R C; Liu, A S

The fluence dependence of Kr precipitation in Ni at room temperature has been studied with the aid of Transmission Electron Microscopy. As in other metals, the Kr precipitates in small cavities. Electron diffraction demonstrates that the Kr precipitates are solid, fcc crystals aligned with each other and the Ni lattice. The trends are similar to those observed for Kr precipitation in Al at room temperature. The average Kr lattice parameter, determined from the electron diffraction, increases with increasing Kr fluence from 0.515 nm to an asymptotic value of 0.545 nm. The asymptotic limit is due to the melting of the larger Kr precipitates. The mismatch between the Kr and Ni lattices is as large as 55%. Diffuse electron scattering was observed from large, liquid, Kr precipitates. This occurs for Kr fluences above 5 x 10/sup 20/ Kr/sup +/m/sup -2/ in Ni and above 2.5 x 10/sup 20/ Kr/sup +/m/sup -2/ in Al. At room temperature, the largest solid Kr precipitate observed in dark field images was 8.3 nm in diameter compared to 4.7 nm in Al. The larger precipitates are liquid or gas. The solid Kr metals at the same lattice parameter in both Ni and Al suggest that the melting is thermodynamic in nature and independent of the host material.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6905521
• Report Number(s): CONF-861207-51; ON: DE87004723
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360106* -- Metals & Alloys-- Radiation Effects
CHARGED PARTICLES
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
FILMS
ION IMPLANTATION
IONS
KRYPTON IONS
METALS
MICROSCOPY
MICROSTRUCTURE
NICKEL
PRECIPITATION
SCATTERING
SEPARATION PROCESSES
THIN FILMS
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY