Tensile strength of thermomechanically processed Cu-9Ni-6Sn alloys

Citation
Jc. Rhu et al., Tensile strength of thermomechanically processed Cu-9Ni-6Sn alloys, MET MAT T A, 30(10), 1999, pp. 2649-2657
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science",Metallurgy
Journal title
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
ISSN journal
1073-5623 → ACNP
Volume
30
Issue
10
Year of publication
1999
Pages
2649 - 2657
Database
ISI
SICI code
1073-5623(199910)30:10<2649:TSOTPC>2.0.ZU;2-U
Abstract
The tensile properties of Cu-9Ni-6Sn alloys with different swaging amounts of 64, 77, and 95 pct, either solutionized and aged (S/A) or directly aged (D/A), were examined as a function of aging time. It was found that the agi ng response of Cu-9Ni-6Sn alloys varied greatly depending on the prior solu tion heat treatment before aging and/or different swaging amounts. The swag ed S/A Cu-9Ni-6Sn alloys showed a multistage increase in tensile strength w ith respect to aging time, probably due to the sequential occurrence of spi nodal decomposition, formation of metastable gamma(.) precipitates, and rec rystallization. The effect of different swaging amounts, ranging from 64 to 95 pct, was minimal on the aging response of S/A specimens. The prior cold working, however, appeared to favor the spinodal strengthening, comparing unswaged and swaged S/A Cu-9Ni-6Sn alloys. In 95 pct swaged D/A Cu-9Ni-6Sn alloys, the level of hardening was much less sensitive to aging time. A com plex interaction between the reduction in dislocation density, the formatio n of equilibrium precipitates, and the reduction of Sn content in the Sn-ri ch segregates during an aging process is believed to be responsible for suc h a lean sensitivity. The increases in tensile strength of 64 and 77 pct sw aged D/A Cu-9Ni-6Sn alloys were found to be much steeper than that in the 9 5 pct counterparts in the early and intermediate stages of aging, which is believed to be related to the relative contribution from work hardening and precipitation hardening to the strength level of D/A specimens.