Equilibrium concentration of interstitials in aluminum just below the melting temperature

The Interstitialcy Theory offers a unified description of the solid, liquid, and amorphous states of condensed matter, including a direct criterion for the onset of melting. A major prediction of the theory is that the equilibrium concentration of interstitial defects should be only about an order of magnitude less than the vacancy concentration near the melting temperature. Of the various properties affected by the presence of interstitials, the shear modulus is known to be particularly sensitive. A non-contact EMAT technique of ultrasonic generation and detection was used to make high temperature measurements of the C44 and C' shear elastic moduli in aluminum. The results show a large C44 deviation just below the melting temperature and a much smaller effect for C', which is to be expected for interstitials in FCC crystals. The results are analyzed to give a detected interstitial concentration of 1.7 ± 0.6 x 10^4 just below the melting temperature of 933 K. This corresponds to a reasonable range for the interstitial formation enthalpy and entropy, and supports the prediction of the Interstitialcy Theory.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Gordon, Craig Alan

Contributors dc:contributor

• Granato, A.V.

• Interstitialcy Theory
• aluminum
• non-contact electromagnetic acoustic transducer

Statement dc:rights

• ©2000 Gordon

Language dc:language

en

Identifier

4280354

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/31251