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Fine-grained copper films on a flexible substrate were cyclically deformed under constant strain range control. It was found that cyclic dislocation plasticity through individual dislocation glide is still dominant at the submicrometer scale, while the ability of irreversible slip of dislocations gradually decreases and the damage was changed from extrusion-induced localization to cracking along grain boundary. Statistical evaluation of the mean spacing between slip bands and/or lines leads to a critical scale (∼28 nm) below which dislocation-controlled cyclic strain localization would be shut down. [ABSTRACT FROM AUTHOR]

Ni-rich Ni x Ti y Nb z (x/y = 1.0645/x-y ≈ 3, z = 0, 2, 4, 6, 9 at.%) alloys were designed and prepared in this work. Based on these alloys, the precipitation evolution of Ni-rich NiTiNb alloys and its influence on phase transformation and mechanical properties were investigated. Ni 4 Ti 3 precipitates are observed in Nb0 and Nb2 alloys after aging and furnace cooling. Ni 4 Ti 3 precipitation sharply increases Ms in Nb0 alloy, however, causes no obvious change of Ms in Nb2 alloy. With increasing Nb addition, large numbers of β-Nb precipitates densely distribute among eutectic regions of Nb6 and Nb9 alloys. β-Nb precipitates and eutectic β-Nb particles decrease Ms. The critical yield stresses of all Ni-rich NiTiNb alloys are determined by Ms , and present same minus linear relationship with Ms. Precipitation and element variation change Ms and then influence mechanical properties. Meanwhile, this result is demonstrated by thermodynamic analysis. • Ni 4 Ti 3 precipitation changes to β-Nb precipitation with increasing Nb addition. • Ni 4 Ti 3 precipitates cause no change of phase transformation in Nb2 alloy. • β-Nb precipitates decrease Ms in NiTiNb alloy. • The critical yield stresses present same minus linear relationship with Ms. [ABSTRACT FROM AUTHOR]