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Metallic Glasses

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Nguyễn Gia Hào

Academic year: 2023

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However, to date, no one has succeeded in producing MG in this alloy system, regardless of the technique used. Despite intensive research in the field of MGs, an understanding of the fundamental link between their structure and properties is still lacking [12–15].

Cluster-based structural models for MGs

In the absence of an atomic description, no systematic design of MGs has been possible, and progress in the field has been based solely on the expensive and inefficient procedure of trial and error. Currently, the structure of MGs is addressed as disordered and our understanding of it is in fact as diffuse and undefined as this term.

The bottom-up approach to MGs

Cluster-assembled metallic glasses, CAMGs

The supersonic expansion of the accretion beam is the other important feature of this source (also common among other accretion sources). The dashed orange line shows the path of the cluster beam from the cluster source through the ion optics and mass filter to the deposition chamber where the clusters gently land on the support material.

Figure 3. A schematic view of the laser vaporization cluster source is illustrated. A laser beam is focused on to a metal target (either pure metal, or an alloy) in the presence of high pressure of a buffer inert gas
Figure 3. A schematic view of the laser vaporization cluster source is illustrated. A laser beam is focused on to a metal target (either pure metal, or an alloy) in the presence of high pressure of a buffer inert gas

Thin-film metallic glasses TFMGs

The facility is composed of a laser evaporation cluster source (grey shade), set of ion optics before and after mass selection (green shading), mass selector (yellow shading), and a deposition chamber (unshaded). The deposition chamber is further equipped with a sputter gun for cleaning the surface of the support material prior to deposition, a residual gas analyzer (RGA) for monitoring the quality of the vacuum in this chamber, and a transfer chamber for sample handling purposes such as removing the sample from this facility for transport to other facilities for analysis and characterization.

Structure–property relation in CAMGs

Zr–Cu CAMGs: the first steps

The good agreement between the observed scattering vector and the literature value may indicate that the structure of the Zr–Cu CAMG is very close to that of rapidly quenched samples. The position of the peak in scattering vector is in excellent agreement with literature values ​​for Zr–Cu MGs of the same composition.

Figure 7. (A) Diffraction patterns of borosilicate glass (solid grey line), cluster-assembled film at room temperature (dashed line), and cluster-assembled film after annealing at 450 K (solid black line) are shown
Figure 7. (A) Diffraction patterns of borosilicate glass (solid grey line), cluster-assembled film at room temperature (dashed line), and cluster-assembled film after annealing at 450 K (solid black line) are shown

The next steps

Although the existence of an amorphous Zr50Cu50 phase in the fabricated CAMG can be confirmed, the wide range of metal clusters used to produce the amorphous film prevents any detailed analysis of the relationship between the film structure and its constituent building blocks. However, some of the future challenges can be expected and a number of research groups are working to solve them.

Author details

Kim, et al., Formation of amorphous phase in the binary Cu-Zr alloy system, Metals and Materials International. Lekka, et al., Structural characterization of Cu(x)Zr(100?x) metallic glasses by molecular dynamics simulations, Journal of Alloys and Compounds.

Structural Features and Properties

Eckert, Atomic structure and transport properties of Cu(50)Zr(45)Al(5) metallic liquids and glasses: molecular dynamics simulations, Journal of Applied Physics, 2011;110. Eckert, Understanding the relationship between atomic structures and transport properties in (Cu0.5Zr0.5)(100–x)Al–x (≤10) glass-forming fluids: molecular dynamics simulations, Journal of Alloys and Compounds.

Structural and Dynamical Properties of Metallic Glassy Films

  • Introduction
  • Models and theoretical methods
  • Structural features in liquid metallic nano‐films during rapid cooling
  • Power‐law scaling of dynamical signatures
  • Synergy and pinning effects of local icosahedral order
  • Origin of the second peak splitting in pair correlation functions
  • Conclusion

Next, the detailed assimilation of Q2D-Is by crystalline zones is examined to investigate the mechanism of the synergy effect. In other words, the Q2D-I is actually a pin, causing the geometric frustration of the surrounding crystalline order. A).

Figure 1 shows the potential energy landscape of the liquid copper nano‐film at the tempera‐
Figure 1 shows the potential energy landscape of the liquid copper nano‐film at the tempera‐

Acknowledgements

The results show that the shoulder peak on the left side of the second peak is due to the appearance of a small amount of the short- or medium-range ordered structures. The structure of 2D disordered films can be a simple mixture of the crystal-like and disordered structural regions.

Structure of the Metallic Glass and Evolution of

Electronical Properties during Glass Transition in Atomic Level

  • Part 1, atomic level structure of metallic glass
  • Part 2, the evolution of structural properties during the glass transition process
  • Part 3, the dynamical properties of the nucleation and glass‐forming process of liquids
  • Part 4, electronic density of states of the glass transition of the alloy
  • Part 5, electronic charge densities of the amorphous solid
  • Part 6, evolution of the electronical properties of the metallic glass
  • Conclusion

Calculated partial bond angle distribution functions of N-Ca-N (N = Ca, Mg, Cu) at different tempera-. Calculated partial bond angle distribution functions of N-Mg-N (N = Ca, Mg, Cu) at different tempera-. Calculated partial bond angle distribution functions of N-Cu-N (N = Ca, Mg, Cu) at different tempera-.

Figure 1. The total paid distribution functions and partial pair distribution functions of the Ca 50 Mg 20 Cu 30  alloy at differ‐
Figure 1. The total paid distribution functions and partial pair distribution functions of the Ca 50 Mg 20 Cu 30 alloy at differ‐

Corrosion Resistance and Electrocatalytic Properties of Metallic Glasses

Corrosion resistances of nonferrous metallic glasses

  • Effect of composition
  • Effect of microstructure
  • Effect of environment

The corrosion resistance of non-ferrous metallic glass of Cu-, Ti-, Zr- and Mg-based alloys will be discussed in the next section. The microstructure and homogeneities of the composition are destroyed by the crystallization, which is necessary to deteriorate the corrosion resistance of metallic glass. 40, 41] reported that the corrosion resistance of Mg-MGs slightly decreased when the in situ second phase or strengthening phase was induced in metallic glass.

Figure 3. Potentiodynamic polarization curves for the alloy in phosphate-buffered solutions at 37°C [15].
Figure 3. Potentiodynamic polarization curves for the alloy in phosphate-buffered solutions at 37°C [15].

Corrosion resistance of Fe-based metallic glass

  • Enhance of minor element addition
  • Effects of microstructure homogeneity
  • Effects of service environment

It shows that the lacier morphologies for devitrified SAM 1651 imply degradation in corrosion resistance. Intuitively, the stronger the aggressiveness of the solution, the weaker the corrosion resistance of metallic glass exhibits. In a word, the corrosion resistance of Fe-based metallic glass decreases with increasing aggressiveness of the solution.

Figure 7. SEM micrographs on the surfaces in 9.7 M H 2 SO 4  solution at 343 K: (a) x = 0.0, (b) x = 2.3, (c) x = 6.3, (d) x = 8.3, (e) x = 12.3 [60].
Figure 7. SEM micrographs on the surfaces in 9.7 M H 2 SO 4 solution at 343 K: (a) x = 0.0, (b) x = 2.3, (c) x = 6.3, (d) x = 8.3, (e) x = 12.3 [60].

Pitting corrosion of metallic glasses

TEM images of the corroded morphologies of the amorphous coating after immersion in 6 M NaCl solution for 1 h (a) and 2 h (b) [105]. TEM images of the corroded morphologies of the amorphous coating after immersion in 6 M NaCl solution for 1 h (a) and 2 h (b) [105].

Figure 12. TEM images of the corroded morphologies of the amorphous coating after immersion in 6 M NaCl solution for 1 h (a) and 2 h (b) [105].
Figure 12. TEM images of the corroded morphologies of the amorphous coating after immersion in 6 M NaCl solution for 1 h (a) and 2 h (b) [105].

Electrocatalytic properties of metallic glasses

Electrocatalytic properties are influenced not only by the composition of the alloy, but also by the surface composition and/or chemically pretreated surface. The increased number of nickel and iron sites by removing the dominant layer of boron oxide, iron oxide and iron oxide after HCl treatment was responsible for the increased catalytic activity, as shown in Figure 15, which means that the activity of the as-received FeB sample was about twice that observed for the FeNiB sample, on the other hand, when comparing the samples etched with HCl, the activity of the FeNiB alloy was about 30 times higher than that of the FeB strip. In the case of the same Tafel slope, the density of the alternating current is mainly influenced by the effective surface area.

Table 6. Electrocatalytic activity parameters of the cathodic hydrogen evolution for G14 and pure Fe, vit.
Table 6. Electrocatalytic activity parameters of the cathodic hydrogen evolution for G14 and pure Fe, vit.

Summary

Glass-forming ability and corrosion resistance of Zr-based Zr-Ni-Al bulk metallic glasses. Effect of additional elements on the corrosion behavior of a Cu-Zr-Ti bulk metallic glass. Mg-based bulk metallic glass composite with high bio-corrosion resistance and excellent mechanical properties.

Structure and Mechanical Behaviour of Cu‐Zr‐Ni‐Al Amorphous Alloys Produced by Rapid Solidification

Methods and materials

Transformation temperatures and thermal effects during transformations were examined by a Perkin-Elmer Sapphire DSC unit in an inert gas atmosphere using a continuous heating mode with a heating rate of 40 K min-1. The annealed strips were investigated by XRD from the surface, cross-sectional SEM under the same conditions as for the quenched strips. Vickers microhardness measurements of the quenched and then annealed strips were performed using a Shimadzu HMV-2 with an applied load of 0.98 N with a dwell time of 10 s at ten different locations.

Results and Discussion

Kissinger plots of the amorphous Cu50Zr40Ni5Al5 alloy produced at a wheel speed of 35 ms-1. Typical cross-sectional SEM images of the Cu50Zr40Ni5Al5 alloy meltspun ribbon prepared at a wheel speed of 35 ms-1. EDX analysis result of the Cu50Zr40Ni5Al5 alloy melt spun ribbon produced at a wheel speed of 35 ms-1as.

Figure 1 shows the X‐ray diffraction patterns of the rapidly solidified Cu 50 Zr 40 Ni 5 Al 5  ribbons produced at wheel surface velocities of 35 and 41 ms -1
Figure 1 shows the X‐ray diffraction patterns of the rapidly solidified Cu 50 Zr 40 Ni 5 Al 5 ribbons produced at wheel surface velocities of 35 and 41 ms -1

Conclusions

Jun, Formation and mechanical properties of bulk Cu–Ti–Zr–Ni metallic glasses with high glass-forming ability. Lee, Formation of Cu-Zr-Ni amorphous powders with significant subcooled liquid region by mechanical alloying technique. Pia, Non-isothermal crystallization kinetics and glass-forming ability of Cu-Zr-Ti-In bulk metallic glasses.

Mechanical Behavior of Zr-Based Metallic Glasses and Their Nanocomposites

Metallic glasses

Ever since the formation of the first metallic glasses in the Au-Si system by rapid solidification, numerous studies have been carried out over the past 15 years due to their attractive properties and technological potential. In the initial period of metallic glass research, high cooling rates on the order of 105 to 106 K/s were the usual requirement for the formation of the glassy phase. MGs have very high yield stress and very high yield strength compared to crystalline steel and Ti alloys (Figure 1(a)).

Quasicrystals

However, in recent years a new class of metallic glass known as bulk metallic glass (BMG) has been synthesized using very slow cooling rates. This composite can be used in airframes and automobiles as an armor piercing material and medical implants. Quasi-crystalline Al-based alloys, e.g. Al-Mn-Ce containing nanoicosahedral particles can be used in surgical blades.

Nanocomposites

QCs are corrosion resistant and have low friction coefficients, so they can be used as a surface coating for pans.

Effect of material tailoring on the mechanical properties

  • Microstructural and structural features
  • Mechanical properties

Plot of the indentation force (P) versus indentation displacement (h) obtained from nanoindentation tests for the as-synthesized (a and b) and annealed (c and d) bands at x = 0 and 7.5, respectively [19]. Thus, the substitution of Ga can increase the packing density of the alloy and this would lead to a decrease in the free volume [41]. The precipitation of nc/nqc phases in the case of composites reduces the free volume and this causes densification of the metallic glass [45].

Figure 3. (a) Optical image showing the formation of long melt-spun ribbons synthesized at 40 m/s
Figure 3. (a) Optical image showing the formation of long melt-spun ribbons synthesized at 40 m/s

Effect of cooling rate on the mechanical properties

  • Microstructural and structural features
  • Mechanical properties

Thermal analysis of the melt-spun Zr69.5Ga7.5Cu12Ni11 ribbons synthesized at different cooling rates. (Reprinted with kind permission from reference [15], Copyright 2015, Elsevier.). 73] have shown that the exothermic heat release is directly related to the structural relaxation, i.e. the change of free volume in metallic glasses, and can be calculated by Figure 14(a) shows characteristic curves of hardness (VHN) versus load (g) for the tapes synthesized at 30, 40 and 50 m/s, respectively.

Figure 9 shows the X-ray diffraction (XRD) patterns of as-synthesized Zr 69.5 Ga 7.5 Cu 12 Ni 11  melt- melt-spun ribbons synthesized at different wheel speeds
Figure 9 shows the X-ray diffraction (XRD) patterns of as-synthesized Zr 69.5 Ga 7.5 Cu 12 Ni 11 melt- melt-spun ribbons synthesized at different wheel speeds

Conclusion

Tripathi Synthesis and mechanical properties of Zr69.5Ga7.5Cu12Ni11 metallic glass composites and nanoquasicrystal-glasses. Thermal and mechanical properties of Zr53Cu30Ni9Al8-based metallic glass microalloyed with silicon. Effect of cooling rate on flexural plasticity of Zr55Al10Ni5Cu30 bulk metallic glass.

Applications

Synthesis and pitting behavior of amorphous and nanocrystalline phases in rapidly quenched Cu-Ga-Mg-Ti and Cu-Al-Mg-Ti alloys. Glass forming ability, thermal stability and indentation properties of Ce60Cu25Al15-xGax (0 ≤ x ≤ 4) metallic glasses. On the prospects of using metallic glasses for mirrors in vessels for plasma diagnostics in ITER.

On the Prospects of Using Metallic Glasses for In-vessel Mirrors for Plasma Diagnostics in ITER

Experimental and precharacterization

  • Descriptions of specimens
  • Pretreatment and initial reflectance
  • Heterogeneities observed in the body of BMG samples
  • Plasma exposure and methods of surface analysis

From this result, it is not surprising that the scattering rate of inhomogeneity. Elemental composition of the mirror material from stage #1: nominal (second column) and measured by the microprobe method in the matrix and in inhomogeneity (ignoring Be). SEM images of mirror surface: (a) Stage #3 sample after argon ion sputtering ~5 μm layer, (b) Stage #4 sample after deuterium plasma ion sputtering ~1 μm layer.

Figure 2. Initial reflectance R 0 (λ) measured just after cleaning by low-energy ions of deuterium or argon plasma of samples of the five grades together with the data for W and Mo from literature [7].
Figure 2. Initial reflectance R 0 (λ) measured just after cleaning by low-energy ions of deuterium or argon plasma of samples of the five grades together with the data for W and Mo from literature [7].

Properties after plasma exposure

  • Absorption of deuterium 1. Amorphous specimens
  • Sputtering rate
  • Modification of optical properties of amorphous mirrors 1. Impact of deuterium plasma ions
  • Role of chemical processes
  • Blisters

SEM images of the crystallized sample of stage #2 after the last exposure (#9) shown in Table 6 [18]. Due to the small size (Ø5 mm in diameter) of Class #3 samples, deuterium adsorption was not quantitatively measured for these samples (too low mass gain). Interference fringes on the surface of stage #3 sample after long-term firing through the mesh (a) and the relief structure determined by processing the interference fringes (b) [20].

Table 3. Results of sequential exposures of one sample of grade #1 in deuterium plasma.
Table 3. Results of sequential exposures of one sample of grade #1 in deuterium plasma.

Summary

The shape and size of the ingots are specified by the shape of the mold cavity and the amount of the furnace charge. We observed a group with the very short wavelengths and the very low fluctuations of the brightness of the laser point "a" (the "ideal mirror"). Point "b" (BMG mirror) has three groups of the short and medium wavelengths and the middle variations of brightness.

Figure A1. The photos of the ingot with cut off upper and lower “caps” before (left) and after (right) cutting into two halves which served as billets for the fabrication of mirror samples.
Figure A1. The photos of the ingot with cut off upper and lower “caps” before (left) and after (right) cutting into two halves which served as billets for the fabrication of mirror samples.

Hình ảnh

Figure 5. (a) The standard deviation (Q sd ) of the total motion propensity and (b) the relationship between the total mo‐
Figure 1. The total paid distribution functions and partial pair distribution functions of the Ca 50 Mg 20 Cu 30  alloy at differ‐
Figure 4. Evolution top seven most populated HA bond‐type index in the Ca 50 Mg 20 Cu 30  alloy as a function of tempera‐
Figure 6. Calculated partial bond‐angle distribution functions of the N‐Ca‐N (N = Ca, Mg, Cu) at different tempera‐
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