Embrittlement of a bulk metallic glass due to low-temperature annealing

Ramamurty, Upadrasta; Lee, Mong Li; Basu, Joysurya; Li, Y

doi:10.1016/s1359-6462(02)00102-1

Cited by 165 publications

(71 citation statements)

References 6 publications

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“…7f. Similar nano-scale periodic corrugations have also been found on the fracture surfaces of high-velocity plate impact tests of Vit1 [17], the brittle Mg-based BMGs [31,32] and the impact test samples of relaxed Zr-based BMG [9,10,16,33]. The fracture toughness K c of this 653 K annealed sample at 77 K was calculated to be $1.3 MPa ffiffiffiffi m p through Eq.…”

Section: Resultssupporting

confidence: 65%

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Shear transformation zone volume determining ductile–brittle transition of bulk metallic glasses

et al. 2011

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Three-point bending experiments were performed on as-cast and annealed samples of Zr 52.5 Cu 17.9 Ni 14.6 Al 10 Ti 5 (Vit105) bulk metallic glasses over a wide range of temperatures varying from room temperature (293 K) to liquid nitrogen temperature (77 K). The results demonstrated that the free volume decrease due to annealing and/or cryogenic temperature can reduce the propensity for the formation of multiple shear bands and hence deteriorate plastic deformation ability. We clearly observed a sharp ductile-to-brittle transition (DBT), across which microscopic fracture feature transfers from micro-scale vein patterns to nano-scale periodic corrugations. Macroscopically, the corresponding fracture mode changes from ductile shear fracture to brittle tensile fracture. The shear transformation zone volume, taking into account free volume, temperature and strain rate, is proposed to quantitatively characterize the DBT behavior in fracture of metallic glasses.

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Section: Resultssupporting

confidence: 65%

“…It is therefore expected that these materials should not undergo DBT process. However, the DBT phenomena, as first reported by Wu and Spaepen [6], have been widely observed in metallic glasses [7][8][9][10][11][12][13][14][15][16]. Due to the practical and scientific significance of this behavior, it has attracted much attention.…”

Section: Introductionmentioning

confidence: 94%

Shear transformation zone volume determining ductile–brittle transition of bulk metallic glasses

et al. 2011

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“…These nano-scaled dimples were typical fracture features of quasi cleavage brittle fracture of metallic glasses under tensile stress. 9,[24][25][26] For the compressive samples which failed with shear fracture at 293 K and 173 K, micron scaled vein pattern regions were dominant in the two fracture surfaces, which are in agreement with these of other ductile BMGs. 18,23 While the samples failed in three pieces at 77 K, shear fracture surface with micron-scaled vein patterns and another fracture surface matched with nano-scaled vein dimples the same as tensile fracture surface shown in Figs.…”

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confidence: 80%

Temperature-induced ductile-to-brittle transition of bulk metallic glasses

Jiang

et al. 2013

Applied Physics Letters

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Uniaxial tensile and uniaxial compressive tests for Zr-based bulk metallic glasses (BMGs) were conducted at room and cryogenic temperatures, respectively. It was observed that both the change of macroscopic fracture mode from ductile shear fracture to brittle normal tensile fracture and microscopic fracture feature from micron-scaled vein patterns to nano-scaled dimples with decreasing test temperatures were identified, indicating a significant ductile-to-brittle transition (DBT) behavior. The mechanism of DBT behavior was revealed by the competition between the intrinsic critical shear strength τ0 and critical tensile strength σ0 at different temperatures.

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“…[14][15][16][17][18][19][20] It has also been reported recently that significant changes of physical properties occur in terms of flow behavior, magnetic and electrical properties and especially embrittlement characteristics due to structural relaxation followed by nanocrystallization, which can be viewed as a natural phenomenon exhibited in non-equilibrium amorphous alloys. [21][22][23][24][25][26][27] It is, thus, indispensable to understand the relationship between the annealing treatment in the supercooled liquid region and the mechanical properties in order to provide feasible forming conditions in terms of processing temperature, strain rate and annealing time.…”

Section: Introductionmentioning

confidence: 99%

Structural Relaxation and Crystallization of a Zr44Ti11Cu9.8Ni10.2Be25 Bulk Metallic Glass

et al. 2007

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The influence of annealing on the structural changes and the room temperature mechanical properties of a Zr 44 Ti 11 Cu 9:8 Ni 10:2 Be 25 bulk metallic glass has been investigated. The structural evolution upon relaxation or crystallization after annealing at a temperature within the supercooled liquid region was studied by thermal analysis, x-ray diffraction, transmission electron microscopy, extended x-ray absorption fine structure and dilatometer measurements. The effects of structural relaxation and nanocrystallization on the mechanical properties were also examined by hardness and compression tests using specimens annealed for various times. The apparent disappearance of plastic strain was found to be due to embrittlement induced by considerable crystallization of the amorphous phase.

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Embrittlement of a bulk metallic glass due to low-temperature annealing

Cited by 165 publications

References 6 publications

Shear transformation zone volume determining ductile–brittle transition of bulk metallic glasses

Shear transformation zone volume determining ductile–brittle transition of bulk metallic glasses

Temperature-induced ductile-to-brittle transition of bulk metallic glasses

Structural Relaxation and Crystallization of a Zr<SUB>44</SUB>Ti<SUB>11</SUB>Cu<SUB>9.8</SUB>Ni<SUB>10.2</SUB>Be<SUB>25</SUB> Bulk Metallic Glass

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