Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass

Cao, Qing; Li, Jinfi; Zhou, Yaohe; Jiang, J.Z.

doi:10.1063/1.1862329

Cited by 53 publications

(38 citation statements)

References 24 publications

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“…If the applied cooling rate remains larger than effective R dec c , crystallization during solidification can be avoided and the material would only phase separate during solidification. The finding by Cao et al [41] that phase separation takes place in shear bands with no evidence of crystallization might be an example of this scenario.…”

Section: Prl 96 075503 (2006) P H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Strain Rate Induced Crystallization in Bulk Metallic Glass-Forming Liquid

Lohwongwatana

Schroers²,

Johnson³

2006

Phys. Rev. Lett.

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We report on the solidification of Au 49 Ag 5:5 Pd 2:3 Cu 26:9 Si 16:3 bulk metallic glass under various strain rates. Using a copper mold casting technique with a low strain rate during solidification, this alloy is capable of forming glassy rods of at least 5 mm in diameter. Surprisingly, when the liquid alloy is splat cooled at much higher cooling rates and large strain rates, the solidified alloy is no longer fully amorphous. Our finding suggests that the large strain rate during splat cooling induces crystallization. The pronounced difference in crystallization behavior cannot be explained by the previously observed strain rate effect on viscosity alone. A strain rate induced phase separation process is suggested as one of the explanations for this crystallization behavior. The strain-rate-dependent critical cooling rate must be considered in order to assess the intrinsic glass forming ability of metallic liquid. DOI: 10.1103/PhysRevLett.96.075503 PACS numbers: 61.43.Dq, 64.70.Dv, 64.75.+g, 82.60.Lf In the 1950s, Turnbull predicted that glass formation in metals is possible if heterogeneous nucleation could be suppressed [1]. Shortly after, Duwez and co-workers reported the synthesis of the first metallic glass [2] by rapidly cooling an Au-Si alloy at a rate of approximately 10 6 K=s. In the 1970s, ribbons, splats, powder, droplets, wires, and thin films were the typical forms of early metallic glasses obtained by rapid quenching [3,4]. Pd-Cu-Si alloy system was the first exception -Chen's discovery of this alloy system provided the first evidence that metallic glass could be cast in bulk form [5].During the past few decades, bulk metallic glasses have been discovered in a wide range of alloys [6 -11]. In some alloys, a critical cooling rate to avoid crystallization as low as 0:005 K=s [12] and critical casting thickness of up to 7 cm were reported [13] when heterogeneous nucleation was reduced.With the exception of some exotic bulk metallic glass (BMG) synthesis methods [14 -17], most amorphous alloys have been created by cooling the liquid from above its liquidus temperature. In this case, the intrinsic glassforming ability (GFA) and critical casting thickness, d max , were understood to be completely characterized by the critical cooling rate, R c (see, e.g., [18].)This Letter presents solidification studies on gold bulk metallic glass-forming alloy Au 49 Ag 5:5 Pd 2:3 Cu 26:9 Si 16:3 , which could be cast into fully amorphous rods of at least 5 mm in diameter using a conventional copper mold injection method. When the liquid alloy was splat cooled, where it was exposed to both high cooling rate and high strain rate, it crystallized during solidification. This suggests that the high strain rate induces crystallization. This effect becomes less pronounced with increasing processing temperature.Ingots of Au 49 Ag 5:5 Pd 2:3 Cu 26:9 Si 16:3 alloy were prepared by arc-melting the elements (purity: Au, 99.95%; Cu, 99.9%; Ag, 99.5%; Pd, 99.95%; Si, 99.95%) in a titaniumgettered, argon-filled atmosphere. Fu...

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Section: Prl 96 075503 (2006) P H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Strain Rate Induced Crystallization in Bulk Metallic Glass-Forming Liquid

Lohwongwatana

Schroers²,

Johnson³

2006

Phys. Rev. Lett.

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“…Recently, some BMGs with relatively large plastic strain were developed, and the potential mechanisms for the enhanced macroscopic plasticity of the BMGs were proposed based upon theoretical and experimental results. [10][11][12][13][14][15] From the theoretical approach, [12,[16][17][18] the flow of metallic glassforming liquids and the flow and fracture of metallic glasses and their relation to elastic constants, i.e.,…”

Section: Introductionmentioning

confidence: 99%

Combinatorial Influence of Bimodal Size of B2 TiCu Compounds on Plasticity of Ti-Cu-Ni-Zr-Sn-Si Bulk Metallic Glass Composites

Hong

Kim

Lee

et al. 2013

Metall Mater Trans A

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We report on the formation of Ti-Cu-Ni-Zr-Sn-Si bulk metallic glass composites containing bimodal size of B2 TiCu compounds. The small B2 TiCu compound with a size of 1 to 10 lm has a strong influence on the oscillation of the shear stress, thus causing wavy propagation of the shear bands. In contrast, the large B2 TiCu compound with a size of 70 to 150 lm dissipates the shear stress by branching and multiplication of the shear bands. By forming the bimodal size of B2 TiCu compound, it is possible to determine the harmonic influence to further enhance the plasticity of the Ti-Cu-Ni-Zr-Sn-Si bulk metallic glass composites.

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“…In order to understand the macroscopic plasticity of the BMGs both nano-scale structural and chemical heterogeneities [9][10][11][12][13][14][15][16] have been suggested to offer a low barrier for nucleation of the shear bands, and to generate the multiplication of the shear bands. 1) Furthermore, beyond the ductility issue in the present investigations, one interesting finding is the occurrence of the work hardening under room temperature compression as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…1,2) The plastic flow allows only a few shear bands to be active, causing catastrophic failure of the sample. However, so called ''ductile'' BMGs have been recently developed by fine-tuning the compositions of good glass-forming Zr-, 3) Pt- 4) and Cu-, 5,6) and CuZr- [7][8][9] based alloys. Among them, a Cu 50 Zr 50 BMG on equiatomic binary alloy system has been reported to show unusual compressive plasticity of more than 50%.…”

Section: Introductionmentioning

confidence: 99%

Be Effect on Glass-Forming Ability and Mechanical Properties of Ti-Cu-Co-Zr-Sn Bulk Metallic Glasses

et al. 2006

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A series of Ti 44 Cu 44Àx Co 4 Zr 6 Sn 2 Be x bulk metallic glasses with x ¼ 0{5:1 has been systematically investigated in terms of glass-forming ability and mechanical properties at room temperature. With the small amount of Be addition, the glass forming ability as well as ductility can be significantly increased leading to the fully amorphous rod having the diameter larger than 4 mm and ductility larger than 10%. Upon compressing the bulk metallic glass Ti 44 Cu 38:9 Co 4 Zr 6 Sn 2 Be 5:1 , a work hardening-like behavior that may be attributed to structural heteorgeniety was observed.

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Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass

Abstract: . (2005). Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass.

Cited by 53 publications

References 24 publications

Strain Rate Induced Crystallization in Bulk Metallic Glass-Forming Liquid

Strain Rate Induced Crystallization in Bulk Metallic Glass-Forming Liquid

Combinatorial Influence of Bimodal Size of B2 TiCu Compounds on Plasticity of Ti-Cu-Ni-Zr-Sn-Si Bulk Metallic Glass Composites

Be Effect on Glass-Forming Ability and Mechanical Properties of Ti-Cu-Co-Zr-Sn Bulk Metallic Glasses

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