Something new about the giant deformation of amorphous alloys irradiated with GeV ions

Audouard, Alain; Toulemonde, M.; Szenes, G.; Thomé, L.

doi:10.1016/s0168-583x(98)00466-2

Cited by 11 publications

(13 citation statements)

References 15 publications

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“…[15] it was only predicted that no incubation dose would be necessary if the local heating in the track, i.e., the energy deposition, was sufficiently high as expected for very high electronic stopping power. This prediction has been confirmed experimentally [7,8]. In Ref.…”

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confidence: 59%

“…Defect production has been studied in some detail in [7,8,[27][28][29], in which the electronic excitations dominate in the defect production cross section. We approximate these data here by s f 5 3 10 25 S 2 e nm 4 ͞keV 2 .…”

Section: Incubation Dose For Ion Beam Induced Anisotropic Growth Of Amentioning

confidence: 99%

“…In this energy range, heavy ions with sufficiently high electronic stopping power (S e . 5 keV͞nm) induce in amorphous materials at low temperatures (T irr # 200-300 K) two striking deformation phenomena: (i) anisotropic expansion ("growth") of unstressed amorphous foil samples perpendicular to the ion-beam direction [2-8] and (ii) creep of stressed amorphous samples with creep or stress relaxation rates [7][8][9][10][11][12][13] which are larger by orders of magnitude than those in crystalline or polycrystalline materials.At medium electronic stopping power (5-30 keV͞nm) the occurrence of both deformation phenomena, i.e., (i) and (ii), requires some incubation fluence (dose) f c which depends on the electronic and nuclear stopping powers, irradiation temperature, and amorphous material properties [2,3,5,6].Recently, ion-beam induced anisotropic growth [14-17] and creep (or stress relaxation) [16][17][18] of amorphous materials have been described in terms of viscous flow and shear stress relaxation in locally heated and damaged regions in the vicinity of the ion trajectories. In the case of anisotropic growth, the shear stress, assumed to relax upon temporal local heating in the vicinity of the projectile trajectory, is due to the thermal expansion in the heated cylindrical track whereas in the creep (stress relaxation) it is given simply by the externally applied macroscopic stress.…”

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Incubation Dose for Ion Beam Induced Anisotropic Growth of Amorphous Alloys: Insight into Amorphous State Modifications

2000

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Under energetic ion bombardment, amorphous materials deform plastically in the form of anisotropic growth. At medium electronic stopping power (5 to 30 keV͞nm) this phenomenon starts only after a certain incubation dose depending on values of the electronic stopping power and temperature. This delay is modeled on the basis of the assumption of a drastic irradiation induced viscosity reduction, resulting from accumulation of atomic displacements in the matrix and local material heating in the heavy ion track. A simple analytical expression is derived which is in a good agreement with experimental data for the amorphous alloy Fe 85 B 15 . PACS numbers: 61.80.Jh In the amorphous (or glassy) state, solid materials are far from equilibrium. An important aspect of this nonequilibrium solid state is that it may be realized, at least within short time periods, in a broad spectrum of metastable states with different degrees of relative stability, relaxation times, and activation barriers for these relaxations [1].There are several techniques to amorphize crystalline and to treat amorphous materials, but bombardment with heavy ions is certainly the method where the most extreme conditions can be realized due to the deposited energy being extremely localized and having a high density. Thus, displacement cascades and electronic excitations along the ion trajectory induce rapid heating and cooling in sub-ns time scales and at rates of up to 10 15 K͞s. Under such conditions, an amorphous material may be investigated at temperatures where it would recrystallize within the time scales of "classical" methods. Bombardment of amorphous materials with heavy ions can also considerably influence the relaxation kinetics of the metastable states and may be considered to provide a deeper understanding of the dynamics of the amorphous state.Energetic heavy ions penetrating a solid lose their energy by quasielastic collisions with the target atoms and by electronic excitations characterized, respectively, by "nuclear" and "electronic" stopping powers, S n and S e . We are interested here in ion energies above 1 MeV͞amu where S e dominates the stopping power. In this energy range, heavy ions with sufficiently high electronic stopping power (S e . 5 keV͞nm) induce in amorphous materials at low temperatures (T irr # 200-300 K) two striking deformation phenomena: (i) anisotropic expansion ("growth") of unstressed amorphous foil samples perpendicular to the ion-beam direction [2-8] and (ii) creep of stressed amorphous samples with creep or stress relaxation rates [7][8][9][10][11][12][13] which are larger by orders of magnitude than those in crystalline or polycrystalline materials.At medium electronic stopping power (5-30 keV͞nm) the occurrence of both deformation phenomena, i.e., (i) and (ii), requires some incubation fluence (dose) f c which depends on the electronic and nuclear stopping powers, irradiation temperature, and amorphous material properties [2,3,5,6].Recently, ion-beam induced anisotropic growth [14-17] and creep (or stress ...

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confidence: 59%

Section: Incubation Dose For Ion Beam Induced Anisotropic Growth Of Amentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Incubation Dose for Ion Beam Induced Anisotropic Growth of Amorphous Alloys: Insight into Amorphous State Modifications

2000

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“…Metallic materials are in general less sensitive to SHII due to their high electron mobility, with the exception of a few selected metals (e.g. Bi [19], Zr, Co, Ti [20] and Fe [21,22]), crystalline alloys [23] and various amorphous metallic alloys [24][25][26][27][28][29][30][31][32][33]. Evidence for the sensitivity of amorphous metals to SHII was demonstrated by Klaumünzer et al [24,25,31], who observed the appearance of irreversible anisotropic plastic deformation.…”

Section: Introductionmentioning

confidence: 99%