Long-term annealing of high purity aluminum single crystals: New insights into Harper-Dorn creep

Smith, K K and Kassner, M E and Kumar, P (2017) Long-term annealing of high purity aluminum single crystals: New insights into Harper-Dorn creep. In: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 705 . pp. 1-5.

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Abstract

Single crystals of 99.999% and 99.9999% pure aluminum were annealed at high elevated temperatures (0.98T(m)) for relatively long times of up to one year, the longest in the literature. Remarkably, the dislocation density remains relatively constant at a value of about 10(9) m(-2) over a period of one year. The stability suggests some sort of ``frustration'' limit. This has implications towards the so-called ``Harper-Dorn creep'' that generally occurs at fairly high temperatures (e.g. > 0.90T(m)) and very low stresses. It is possible that ordinary five-power-law creep occurs within the tradition Harper-Dorn regime with very low initial dislocation densities in aluminum. Higher initial dislocation densities, such as with this annealing study, may lead to Harper-Dorn (Newtonian) creep.

Item Type:	Journal Article
Publication:	MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	11 Nov 2017 05:26
Last Modified:	11 Nov 2017 05:26
URI:	http://eprints.iisc.ac.in/id/eprint/58214

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