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On the Estimation of True Hall–Petch Constants and Their Role on the Superposition Law Exponent in Al Alloys
Author(s) -
Thangaraju Shanmugasundaram,
Heilmaier Martin,
Murty Budaraju Srinivasa,
Vadlamani Subramanya Sarma
Publication year - 2012
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201200114
Subject(s) - superposition principle , materials science , exponent , grain size , grain boundary strengthening , grain boundary , range (aeronautics) , condensed matter physics , constant (computer programming) , thermodynamics , metallurgy , composite material , mathematical analysis , mathematics , physics , microstructure , philosophy , linguistics , computer science , programming language
Hall–Petch (HP) relation and the superposition of different strengthening mechanisms in different aluminum alloys with grain sizes in the range of 50 nm–70 µm were analyzed. HP parameters as high as σ 0 ≈ 200 MPa and k HP ≈ 0.14 MPa m 1/2 were observed when the HP relation was fitted directly using the experimentally measured yield strength values. In contrast, considering only the grain size strengthening (by subtracting other strengthening contributions), HP constants of σ 0 ≈ 10 MPa and k HP ≈ 0.06 MPa m 1/2 were obtained over wide range of grain sizes for the case of a linear superposition of the various strengthening mechanisms present. This is in excellent accord with the values obtained for pure Al justifying the chosen superposition exponent of n equal unity for the different alloys investigated.