CONSTITUTIVE BEHAVIOR OF COMPOSITES OF AA6061 AND ALUMINA

Citation
Chj. Davies et al., CONSTITUTIVE BEHAVIOR OF COMPOSITES OF AA6061 AND ALUMINA, Journal of materials processing technology, 70(1-3), 1997, pp. 244-251
Citations number
20
Categorie Soggetti
Material Science
ISSN journal
09240136
Volume
70
Issue
1-3
Year of publication
1997
Pages
244 - 251
Database
ISI
SICI code
0924-0136(1997)70:1-3<244:CBOCOA>2.0.ZU;2-A
Abstract
Metal-matrix composites are being used increasingly for the fabricatio n of engineering components, yet the response of such materials to def ormation is still poorly characterised. In an attempt to further the o ptimisation of processing, the constitutive behaviour of the composite s 6061/Al2O3/10p and 6061/Al2O3/20p has been investigated; for compari son purposes, the unreinforced alloy was tested also. Compression test ing was carried out at strain rates of between 0.01 and 10s(-1), at te mperatures of between 300 and 550 degrees C. The resulting data were f itted to the hyperbolic sine relationship and an internal stress relat ionship. It was found that the constitutive behaviour of unreinforced alloy could be characterised adequately by a single relationship over the whole temperature range, whereas the behaviour of the composites w as best described in two temperature ranges, above and below about 425 degrees C. The hyperbolic sine relationship was found to be the more accurate in each case, however, for extrapolating to lower temperature s, the internal stress relationship was found to be more reliable for the composites. The change in constitutive behaviour at 425 degrees C is related to the controlling mechanism in the two temperature regimes : precipitation of beta' at low temperatures, and dynamic recrystallis ation at high temperatures. This observation may need to be accounted for in the commercial production of metal-matrix composites. (C) 1997 Elsevier Science S.A.