Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite

Abstract

The outstading mechanical properties of bimodal ultrafine eutectic composites (BUECs) containing length scale hierarchy in eutectic structure were demonstrated by using AFM observation of surface topography with quantitative height measurements and were interpreted in light of the details of the deformation mechanisms by three different interface modes. It is possible to develop a novel strain accommodated eutectic structure for triggering three different interface-controlled deformation modes; (I) rotational boundary mode, (II) accumulated interface mode and (III) individual interface mode. A strain accommodated microstructure characterized by the surface topology gives a hint to design a novel ultrafine eutectic alloys with excellent mechanical properties.

Dislocations interaction induced structural instability in intermetallic Al2Cu

“…1 Almatrix structural alloys that contain Al-based intermetallic precipitates are potential candidates for structural applications at ambient and elevated temperatures because of their significantly lightweight, four times lower density as compared to steel. [2][3][4][5][6][7][8][9][10] Through refining the characteristic dimension and distribution of intermetallic precipitates, the ductility and strength of Al-matrix composites can be significantly improved at room temperature. A high volume fraction of nanoscale intermetallic reinforcements (precipitate or lamina) can be realized with the help of either rapid solidification with alloying additions (for example, the directional solidification of metal-intermetallic lamellar eutectics) [2][3][4][5][6][7] or severe plastic deformation (SPD) techniques.…”

“…[2][3][4][5][6][7][8][9][10] Through refining the characteristic dimension and distribution of intermetallic precipitates, the ductility and strength of Al-matrix composites can be significantly improved at room temperature. A high volume fraction of nanoscale intermetallic reinforcements (precipitate or lamina) can be realized with the help of either rapid solidification with alloying additions (for example, the directional solidification of metal-intermetallic lamellar eutectics) [2][3][4][5][6][7] or severe plastic deformation (SPD) techniques. [8][9][10][11][12] However, SPD often leads to destabilization of intermetallic phase, such as the formation of non-equilibrium solid solutions, 8,9 disordering 10,11 or amorphization.…”

Mechanism of lamellae deformation and phase rearrangement in ultrafine β-Ti/FeTi eutectic composites

“…The enhancement of strength up to 2 GPa in UECs has occurred due to the presence of hard intermetallic nano-lamellar phase(s) in the matrix of Ti-Cu-Ni-Sn-Nb [22], Zr-Cu-Ni-Al-Nb [23], Ti-FeSn [13][14][15][16][17], Fe-Nb-(Al/Mn/Ni) [3,24], Al-Cu-Si [25], and Ni-Zr [4,26,27]. Whereas, the improvement of compressive plasticity of UECs have been interlinked with the formation of large number of shear bands [28,29], and localized rotation of the colony boundaries to effectively dissipate the shear stress [10,11,[20][21][22]25], which have been further assisted due to the change in the lamellar morphology upon alloy additions [21].…”

“…Whereas, the improvement of compressive plasticity of UECs have been interlinked with the formation of large number of shear bands [28,29], and localized rotation of the colony boundaries to effectively dissipate the shear stress [10,11,[20][21][22]25], which have been further assisted due to the change in the lamellar morphology upon alloy additions [21]. Hence, the ternary alloy addition must tuned the lamellar microstructure in UECs, and has tailored their mechanical properties.…”

Phase Transformation and Work-hardening Behavior of Ti-based Bulk Metallic Glass Composite

“…In order to understand origins of work-hardening behavior in current BMGC, nano-indentation technique was employed. It is known that the nano-indentation test combined with microscopic analysis is effective way to evaluate the relationship between micro-/nano-scale structural evolution and corresponding mechanical properties (Wu et al, 2010;Zhang et al, 2013;Kim et al, 2014;Lee et al, 2014aLee et al, , 2014b. Fig.…”