Channel die tests on Al and Cu polycrystals: Study of the prestrain history effects on further large strain texture
Al and Cu polycrystals have been prestained in a channel die to a compressive strain of 0.04-0.08 (small prestrain) and 0.40-0.55 (large prestrain) and then secondarily strained in different orientations - still in the channel die - up to a second strain of 0.75 in compression. The polycrystal hardening anisotropy is measured at small and large strain and reported under a form similar to the latent hardening ratio curves for single crystals, say here the ratio of the initial (back extrapolated) yield stress for the secondary straining to the maximum stress at the end of the prestrain. Texture measurements have been performed at the end of the secondary straining for the copper samples and are reported under the form of )111), )200) and )110) pole figures. The observed differences on the measured textures are discussed with regard to the prestrain orientation and amplitude with special attention to the associated polycrystal hardening anisotropy and its more probable causes, geometrical or microstructural. The main observations are: (1) for copper, there is a hardening anisotropy after small strains which does not seem due to texture but to an intracrystalline latent hardening effect. This hardening anisotropy depends on the way the load path is changed and differs for the various secondary orientations. A weak hardening anisotropy occurs after large strains where one can expect more effect of the associated texture which appears to act in the opposite direction of that due to the latent hardening. The correlation between changes on deformation textures at large strain and path changes during loading appears as follows: while a path change after a large prestrain has a strong effect on the texture pattern after a secondary strain of 0.75 both on intensity and location of the maxima, it has only a mild effect after a weak prestrain.
- Research Organization:
- Laboratoire PMTM, CNRS, avenue J. B. Clement, 93430 Villetaneuse
- OSTI ID:
- 5524999
- Journal Information:
- Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 35:8; ISSN AMETA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
ALUMINIUM
ANISOTROPY
COPPER
CRYSTAL STRUCTURE
CRYSTALS
DESTRUCTIVE TESTING
ELEMENTS
HARDENING
MATERIALS TESTING
METALS
MICROSTRUCTURE
POLYCRYSTALS
STRAINS
STRESS ANALYSIS
STRUCTURAL CHEMICAL ANALYSIS
TESTING
TEXTURE
TRANSITION ELEMENTS