Microstructure and Aging Behavior of Cu-Be Alloy Processed by High-Pressure Torsion

Abstract:

The microstructure and aging behavior of Cu-1.8wt%Be-0.2wt%Co alloy specimens processed by high-pressure torsion (HPT) at room temperature (RT) and 150°C after solution treatment have been studied. Application of HPT processing at RT and 150°C under an applied pressure of 5 GPa for 10 revolutions at 1 rpm to alloy specimens (RT-and 150°C-specimen) produces an ultra-fine grained structure with a grain size of 70 nm. The hardnesses of the RT-and 150°C-specimens increase with equivalent strain up to 7 and then saturate at constant values of 400 and 430 Hv, respectively. Annealing the RT-specimen at 150°C for 10 min increases the hardness from 400 to 430 Hv. Transmission electron microscopy observations of the 150°C-specimen and the RT-specimen annealed at 150°C reveal that there are no intragranular and intergranular precipitates. It is suggested that the higher hardness of the 150°C-specimen than the RT-specimen is ascribed to the segregation of Be atoms on dislocations during HPT processing at 150°C. The RT-and 150°C-specimens harden rapidly and exhibit maximum values of hardness at 3 min during aging at 320°C. The increase in the hardness is attributed to the precipitation of finely dispersed G.P. zones.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 2707-2712
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.2707
• Online since: May 2014
• Authors: Chihiro Watanabe*, Ryoichi Monzen, Seiichiro Ii, Koichi Tsuchiya
• Keywords: Age-Hardening, Cu-Be System Alloy, High-Pressure Torsion, Microstructure

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