The effect of grain size on the high-strain, high-strain-rate behavior of copper

Meyers, Marc A and Andrade, Umberto R and Chokshi, Atul H (1995) The effect of grain size on the high-strain, high-strain-rate behavior of copper. In: Metallurgical and Materials Transactions A, 26 (11). pp. 2881-2893.

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Abstract

Copper with four widely differing grain sizes was subjected to high-strain-rate plastic deformation in a special experimental arrangement in which high shear strains of approximately 2 to 7 were generated. The adiabatic plastic deformation produced temperature rises in excess of 300 K, creating conditions favorable for dynamic recrystallization, with an attendant change in the mechanical response. Preshocking of the specimens to an amplitude of 50 GPa generated a high dislocation density; twinning was highly dependent on grain size, being profuse for the 117- and 315-mu m grain-size specimens and virtually absent for the 9.5-mu m grain-size specimens. This has a profound effect on the subsequent mechanical response of the specimens, with the smaller grain-size material undergoing considerably more hardening than the larger grain-size material. A rationale is proposed which leads to a prediction of the shock threshold stress for twinning as a function of grain size. The strain required for localization of plastic deformation was dependent on the combined grain size/shock-induced microstructure, with the large grain-size specimens localizing more readily. The experimental results obtained are rationalized in terms of dynamic recrystallization, and a constitutive equation is applied to the experimental results; it correctly predicts the earlier onset of localization for the large grain-size specimens. It is suggested that the grain-size dependence of shock response can significantly affect the performance of shaped charges.

Item Type:	Journal Article
Publication:	Metallurgical and Materials Transactions A
Publisher:	The Minerals, Metals & Materials Society
Additional Information:	Copyright of this article belongs to The Minerals, Metals & Materials Society.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	27 May 2011 05:38
Last Modified:	27 May 2011 05:38
URI:	http://eprints.iisc.ac.in/id/eprint/37957

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