Oxidation and crystallization of Zr-based bulk metallic glass due to machining

Bakkal, Mustafa; Liu, Chang; Watkins, Thomas R.; Scattergood, R.O.; Shih, Albert J.

doi:10.1016/j.intermet.2003.09.017

Cited by 86 publications

(42 citation statements)

References 14 publications

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“…When milling at a cutting speed of 200 m/min, flashes of burning chips were often observed, suggesting that temperatures above 2400 K occurred at the interface. 11 These results suggest that this BMG can be reliably machined by dry milling only if low cutting speeds (around 20 m/min) are used, which is consistent with previous reports. 10 Figure 4(b) shows DSC traces of the BMG as-cast and after machining by AWJ, at various feed rates, and EDM at 380 A (representative of DSC for all EDM conditions).…”

Section: Resultssupporting

confidence: 91%

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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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Section: Resultssupporting

confidence: 91%

“…Machining of Zr-based BMGs by milling, 9 turning, 10,11 or drilling 12 has been studied. The respective studies report that temperatures up to 2700 K may arise and that damage to cutting tools, due to the high hardness of the BMG, can occur.…”

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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“…Furthermore, very low thermal conductivity of MGs results in a high local temperature in the cutting region especially during high speed cutting. Thus, oxidation and crystallization of MGs may occur [20] which probably affect their amorphous performances [21,22], but this kind of effects is dependent of the properties and volume fraction of the crystalline phases [21][22][23] as well as the sample preparation and evaluation methods [24,25]. In addition, high local temperature will also increase the adhesion between the chip and tool, leading to the formation of built-up edge on the rake face, and thus affect the subsequent cutting process [16,26].…”

Section: Introductionmentioning

confidence: 99%

Nanosecond pulsed laser irradiation induced hierarchical micro/nanostructures on Zr-based metallic glass substrate

et al. 2016

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• Hierarchical micro/nanostructures were fabricated on a metallic glass substrate by nanosecond pulsed laser irradiation.• It retained amorphous characteristic and exhibited uniform element distribution.• Irradiation parameters induced change from cotton-like to particle-like nanostructure.• Formation mechanism and mechanical properties were investigated. A large effective surface area is beneficial to enhance the applications of metallic glasses (MGs) in heterogeneous catalysis and biomedical engineering. For the purpose of increasing effective surface area, in this study, hierarchical micro/nanostructures were fabricated on a Zr-based MG substrate by nanosecond pulsed laser irradiation. Experimental results indicated that a layer of micron-scale laser pulse tracks covered by a cotton-like MG thin film with nanometer-scale microstructure was formed in the laser irradiated region. This hierarchical micro/nanostructures retained amorphous characteristic and exhibited uniform element distribution. Its formation mechanism was investigated by analyzing the laser irradiation process and morphologies. Nanoindentation results indicated that the cotton-like MG thin film was very loose and soft compared to the as-cast MG substrate, showing different plastic deformation behavior. Results from this study indicate that nanosecond pulsed laser irradiation is an effective method to generate hierarchical micro/nanostructures on MG substrates, which can increase their effective surface areas and improve their potential applications as biomaterials and catalysts.

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“…Recently, Bakkal et al had reported the chip light emission and morphology, cutting forces, surface roughness and tool wear through the investigation of the turning of Zr-based BMG together with an Al alloy and SUS304 stainless steel under the same cutting condition using the different tool materials. [10][11][12] Authors also had presented the cutting force, surface roughness, and cut surface and chip morphology through the investigation of the turning of not only the Zr-based BMG having the large toughness but also Pd-based BMG having the small toughness together with a steel and free-cutting brass under the same cutting conditions using the different tool materials and nose tip radii. 13,14) The results of the author's presents are summarized in this paper.…”

Section: Introductionmentioning

confidence: 99%

Cutting Characteristics of Bulk Metallic Glass

et al. 2005

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The establishment of appropriate machining techniques for bulk metallic glasses (BMGs), which exhibit excellent mechanical, physical and chemical properties, is required to apply the BMGs. In this report, the cutting characteristics of BMGs were examined by turning with different tool materials, nose radii (R n ) and cutting speeds (V). Round bars of Zr 65 Cu 15 Ni 10 Al 10 and Pd 40 Cu 30 Ni 10 P 20 at% BMGs were used as the workpieces. In order to compare the cuttability of the BMGs with that of crystalline alloys, steel (JIS SGD-400D) and free-cutting brass (JIS C3604) were used. The principal cutting force (F H ) and surface roughness (R a ) of the machined surfaces were measured. X-ray diffraction patterns were also obtained from the machined surfaces. The value of R a in the BMGs exhibit the upper end of precise finishing level (i.e., R a ¼ 0:2 mm), and was remarkably lower compared with the steel and a little lower compared with the free-cutting brass in spite of the value of V. The value became smaller with increasing values of R n , exhibiting a very low value of 0.08 mm for an R n value of 1.2 mm. The values of F H in both BMGs did not show a clear difference and were half that of the steel for a V value less than 40 m/min, even though the tensile strength of the BMGs was twice as large as the steel. The chip of the BMGs showed an ideal flow type with very short and regular intervals, formed by planar slip, and revealed very homogeneous, flat and featureless back surfaces. From these observations of chips, it is presumed that the reason for the excellent cuttability of BMGs is due to a slipping-off mechanism at planes of very short intervals decided only by the maximum shear stress and non-built-up edges caused by a low glass transition temperature.

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Oxidation and crystallization of Zr-based bulk metallic glass due to machining

Cited by 86 publications

References 14 publications

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

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

Nanosecond pulsed laser irradiation induced hierarchical micro/nanostructures on Zr-based metallic glass substrate

Cutting Characteristics of Bulk Metallic Glass

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