Microhardness measurements and the Hall-Petch relationship in an Al-Mg alloy with submicrometer grain size
- Kyushu Univ., Fukuoka (Japan). Dept. of Materials Science and Engineering
- Russian Academy of Sciences, Ufa (Russian Federation). Inst. for Metals Superplasticity Problems
- Univ. o Southern California, Los Angeles, CA (United States)
An Al-3% Mg solid solution alloy was subjected to intense plastic deformation, using ether equal-channel angular (ECA) pressing or torsion straining, to produce grain sizes in the submicrometer range. Static annealing at elevated temperatures led to grain growth and average grain sizes of up to >100 {micro}m. As-fabricated and statically annealed specimens were used to determine the variation in microhardness with grain size, and results confirm that the Hall-Petch relationship persists down to at least the finest grain size examined experimentally ({approximately}90 nm). The results provide no evidence to support the claims of a negative Hall-Petch slope when the average grain size is very small, but there is evidence of a decrease in the slope of the Hall-Petch plot at the very finest grain sizes (<150 nm); this is attributed to the increased participation of mobile extrinsic dislocations in the boundary regions when taking the hardness measurements.
- OSTI ID:
- 415446
- Journal Information:
- Acta Materialia, Vol. 44, Issue 11; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
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