Cutting characteristics of bulk metallic glass

Kazutaka Fujita, Yasuo Morishita, Nobuyuki Nishiyama, Hisamichi Kimura, Akihisa Inoue

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)

Abstract

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 (Rn) and cutting speeds (V). Round bars of Zr 65Cu15Ni10Al10 and Pd 40Cu30Ni10P20 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 (FH) 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 Ra in the BMGs exhibit the upper end of precise finishing level (i.e., Ra = 0.2 μm), 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 Rn, exhibiting a very low value of 0.08 μm for an Rn 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.

Original languageEnglish
Pages (from-to)2856-2863
Number of pages8
JournalMaterials Transactions
Volume46
Issue number12
DOIs
Publication statusPublished - 2005 Dec

Keywords

  • Bulk metallic glass
  • Cutting
  • Flow type of chips
  • Lathe
  • Surface roughness
  • Turning

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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