Formation mechanism of shear bands in ultrafine lamellar Ti–Fe eutectics

Abstract

Shear bands with alternating lamellar and serrated structures were observed on the fracture surface of an Ti–Fe ultrafine eutectic. The shear bands are composed of coalesced subgrains. Hence, a subgrain rotational mechanism is proposed to explain their formation. The work is a direct experimental evidence of the hypothetical rotational mechanism.

Origin of plasticity in ultrafine lamellar Ti-Fe-(Sn) composites

“…8 However, some plasticity can be obtained under constrained geometry. 13 Furthermore, it has been reported that addition of Sn refines the interlamellar spacing of Ti 70.5 Fe 29. 5 and improves the plasticity.…”

“…Recently, homogeneous ultrafine composites without any micrometer-size second phase dispersions has been developed in Ti-Fe-Sn, 8,9 Fe-Nb-Al, 10 and Ni-Zr alloys. 11 The deformation mechanism on the improvement of plasticity has been explained due to the change in morphology of the phases upon ternary alloy additions, 9 which helps formation of large number of shear bands, 8,9,12 their rotation 10,11,13 or phase transition. 14 In this letter, we report on the microstructure evolution in differently deformed Ti 68.38 Fe 28.61 Sn 3 ultrafine composites to explore the mechanism of plastic deformation.…”

Enhancement of mechanical properties in a Fe81Nb9B10 ultrafine-eutectic composite with in-situ polygonal pro-eutectic and encapsulating eutectic structure

“…Their distinctive mechanical properties are attributed to the modulation of deformation behavior. Therefore, controlling the characteristics of deformation bands is very important for more durability and reliability of heterogeneous ultrafine composites [14][15][16][17][18][19]. However, unsolved serious issue about the typical trade-off between strength and plasticity still remains.…”

Deformation mechanisms to ameliorate the mechanical properties of novel TRIP/TWIP Co-Cr-Mo-(Cu) ultrafine eutectic alloys

“…render them unsuitable for engineering applications1234. Various countermeasures for improving ductility have been reported for eutectic alloys via controlling the propagation of shear bands through introducing a bimodal (or multi-modal) microstructure347101112131415. For instance, ultrafine eutectic composites with homogeneously embedded primary dendritic phase dispersions have been reported for a variety of Ti-116, Fe-410 and Al-based14 alloy systems, which present a superior combination of both high strength and improved plasticity.…”

“…More recently, microstructural tailoring of UEAs without primary toughening phases such as in the case of duplexed microstructural (structural and/or chemical) eutectic alloys has been proposed in Ti-1117, Al-3 and Fe-based12 UEAs. The detailed deformation mechanisms responsible for the improvement of plasticity without tradeoff between strength and plasticity have been interpreted by the evolved morphology of eutectic colonies, which can lead to the formation of a large number of shear bands24710, their rotation motion with wavy propagation of shear bands111213.…”