Fabrication and characterization of metallic glasses with a specific microstructure for micro-electro-mechanical system applications

Chen, X.H.; Zhang, X.C.; Zhang, Y.; Chen, G.L.

doi:10.1016/j.jnoncrysol.2008.01.030

Cited by 35 publications

(20 citation statements)

References 23 publications

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“…For producing attractive for various applications micro-and nanoporous structures different types of alloys have been used: two-phase crystalline alloys [7,[11][12][13][14][15][16][17][18][19] single phase solid solutions [10,[20][21][22] as well as fine nanocrystalline and amorphous alloys [4][5][6]14,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. To form uniform nanoporosity upon dealloying, an alloy system is required to be a monolithic phase because the nanoporosity is formed by a self-assembly process through surface diffusion, not by the simple excavation of one phase from a pre-separated multiphase system [28].…”

Section: Introductionmentioning

confidence: 99%

Selective dissolution of amorphous Zr–Cu–Ni–Al alloys

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Selective dissolution of amorphous Zr–Cu–Ni–Al alloys

et al. 2015

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“…Thus future research directions are mainly focused on the BMG composites, and high-entropy alloys [1][2][3][4][5][6] .…”

Section: Shear-band Spacing Bridgman Solidification Bmg Compositesmentioning

confidence: 99%

Shear-band spacing controlled by Bridgman solidification in Dendrite/BMG composites

Wang

Zhang

2009

Sci. China Ser. G-Phys. Mech. Astron.

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The paper reports that the shear-band spacing can be controlled by the Bridgman solidification technique for a model alloy of Zr 38.3 Ti 32.9 Nb 7.3 Cu 6.2 Be 15.3 . The volume percent of the glass phase is almost independent of the withdrawal velocity. The shear-band spacing reaches a minimum of about 3 μm with withdrawal velocity of 0.8 mm/s. The optimized mechanical properties, such as the fracture strength of ~2100 MPa and plastic strain of ~19%, have been obtained. The large plastic deformation is due to the dislocation slips in the dendrite phase and shear-band propagations in the glass phase. Shear-band spacing, Bridgman solidification, BMG compositesBulk metallic glasses (BMGs) exhibit many unique properties, such as ultrahigh strength which is about two or three times stronger than the crystalline materials, high elastic strain limits as high as about 2%; super-plastic behavior in the supercooled liquid region; ductile for the smaller sample; and low melting temperature because of the near eutectic composition. Thus future research directions are mainly focused on the BMG composites, and high-entropy alloys [1][2][3][4][5][6] .BMG composites are usually prepared by the copper-mould suction casting. However, the samples prepared by copper-mould suction casting contain inhomogeneous dendrites in the glass matrix, due to the decreasing cooling rates from the outer surface to the center of the rod-shape samples, which leads to large deviation from that of the reported mechanical properties [7] . Another drawback of the suction casting comes from the pores that easily form during the suction of the viscous liquid into the copper mould and that also deteriorate the tensile mechanical properties. Figure 1(a) shows the sample used in the tensile tests, Figure 1(b) shows a pore on the fracture surface after the tensile test, and Figure 1(c) shows the tensile stress-strain curve. The inset in Figure 1(c) is the XRD pattern which shows the alloy Cu 46 Zr 47 Al 7 is of BMG composite [8] . The formation of pores reduces the actual area for the tensile loading, and leads to the lower fracture strength.This paper used Bridgman Solidification to overcome the problem by adjusting the withdrawal velocities (V) in a controlled manner, and composites with different length scale of dendrite were obtained. In this paper, the relationship between the shear-bands spacing (λ) and the technical parameter, V, was founded, and this provides a technical method to improve the plasticity of the dendrite/BMG composites.

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“…The effects of laser micromachining of a Zr-Cu-Al BMG with a CO 2 laser have been examined, 13 showing formation of crystalline grains in the heat-affected zone and contraction due to recrystallization in the melted zone. Noncontact micro-electrical discharge a) machining (EDM) of the surface of a BMG has also been explored 14,15 and was found to be nondestructive. Abrasive waterjet (AWJ) machining 16 is an attractive alternative to the above methods.…”

Section: Introductionmentioning

confidence: 99%

Abrasive waterjet machining of three-dimensional structures from bulk metallic glasses and comparison with other techniques

et al. 2012

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Bulk metallic glasses (BMGs) are a promising class of engineering materials, but they can be difficult to machine due to high hardness and a metastable structure. Crystallization due to machining can have negative effects, such as a decreased load-bearing capacity of fabricated parts, and thus should be avoided. Here, a Zr-based BMG was machined using abrasive waterjet (AWJ), electrical discharge, ns-pulsed laser engraving, and conventional dry-milling techniques. Characterization of the processed material indicated that AWJ preserves the amorphous phase and provides the combination of speed and flexibility required to rapidly fabricate small threedimensional parts, while the other techniques did not achieve these goals. As proof-of-principle, a screw, similar to an orthopedic implant, was rapidly machined from the BMG using AWJ.

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Fabrication and characterization of metallic glasses with a specific microstructure for micro-electro-mechanical system applications

Cited by 35 publications

References 23 publications

Selective dissolution of amorphous Zr–Cu–Ni–Al alloys

Selective dissolution of amorphous Zr–Cu–Ni–Al alloys

Shear-band spacing controlled by Bridgman solidification in Dendrite/BMG composites

Abrasive waterjet machining of three-dimensional structures from bulk metallic glasses and comparison with other techniques

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