Atomic-scale structural heterogeneity and elastic modulus for metallic glasses

2015 ◽  
Vol 426 ◽  
pp. 137-140 ◽  
Author(s):  
Haishun Liu ◽  
Qingling Liu ◽  
Hai Su ◽  
Weiming Yang ◽  
Yucheng Zhao ◽  
...  
2018 ◽  
Vol 101 ◽  
pp. 133-143 ◽  
Author(s):  
X.J. Liu ◽  
S.D. Wang ◽  
H.Y. Fan ◽  
Y.F. Ye ◽  
H. Wang ◽  
...  

2021 ◽  
Vol 202 ◽  
pp. 114033
Author(s):  
J.H. Yu ◽  
L.Q. Shen ◽  
D. Şopu ◽  
B.A. Sun ◽  
W.H. Wang

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 929
Author(s):  
Dandan Liang ◽  
Jo-Chi Tseng ◽  
Xiaodi Liu ◽  
Yuanfei Cai ◽  
Gang Xu ◽  
...  

This study investigated the structural heterogeneity, mechanical property, electrochemical behavior, and passive film characteristics of Fe–Cr–Mo–W–C–B–Y metallic glasses (MGs), which were modified through annealing at different temperatures. Results showed that annealing MGs below the glass transition temperature enhanced corrosion resistance in HCl solution owing to a highly protective passive film formed, originating from the decreased free volume and the shrinkage of the first coordination shell, which was found by pair distribution function analysis. In contrast, the enlarged first coordination shell and nanoscale crystal-like clusters were identified for MGs annealed in the supercooled liquid region, which led to a destabilized passive film and thereby deteriorated corrosion resistance. This finding reveals the crucial role of structural heterogeneity in tuning the corrosion performance of MGs.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hosni Idrissi ◽  
Matteo Ghidelli ◽  
Armand Béché ◽  
Stuart Turner ◽  
Sébastien Gravier ◽  
...  

Abstract The fundamental plasticity mechanisms in thin freestanding Zr65Ni35 metallic glass films are investigated in order to unravel the origin of an outstanding strength/ductility balance. The deformation process is homogenous until fracture with no evidence of catastrophic shear banding. The creep/relaxation behaviour of the films was characterized by on-chip tensile testing, revealing an activation volume in the range 100–200 Å3. Advanced high-resolution transmission electron microscopy imaging and spectroscopy exhibit a very fine glassy nanostructure with well-defined dense Ni-rich clusters embedded in Zr-rich clusters of lower atomic density and a ~2–3 nm characteristic length scale. Nanobeam electron diffraction analysis reveals that the accumulation of plastic deformation at room-temperature correlates with monotonously increasing disruption of the local atomic order. These results provide experimental evidences of the dynamics of shear transformation zones activation in metallic glasses. The impact of the nanoscale structural heterogeneities on the mechanical properties including the rate dependent behaviour is discussed, shedding new light on the governing plasticity mechanisms in metallic glasses with initially heterogeneous atomic arrangement.


2011 ◽  
Vol 107 (21) ◽  
Author(s):  
P. Murali ◽  
T. F. Guo ◽  
Y. W. Zhang ◽  
R. Narasimhan ◽  
Y. Li ◽  
...  

2004 ◽  
Vol 370 (1-2) ◽  
pp. 302-306 ◽  
Author(s):  
Y. Hiki ◽  
T. Yagi ◽  
T. Aida ◽  
S. Takeuchi

2008 ◽  
Vol 8 (6) ◽  
pp. 3123-3135 ◽  
Author(s):  
Pradip Paik ◽  
Kamal K. Kar

The high molecular weight (MW) polyethylene (PE) particles of particle size varied from macro to micron to nanometer were synthesized by Grignard reagent. The microscopy analysis (scanning electron microscope, SEM; transmission electron microscope, TEM; and atomic force microscope, AFM) shows the spherical shape of PE particles. The effects of particle size, varies from macro to nanometer scale on crystal structure, crystallinity (χc), glass transition temperature (Tg), melting temperature (Tm), surface roughness and mechanical properties were studied. Differential scanning calorimetry (DSC) experiments show that the nanoparticles of PE are highly crystalline (χc ≈ 72%). The crystal length of PE nanoparticles is found to be approximately 14 Å. Although the Gibbs-Thomson equation is explained the depression of melting temperature (ΔTm) by 5 °C, the impervious results of Tg are still not fully understood. The low roughness value (2 Å) proves the presence of "atomic-scale-chain" folding at the surface of PE nanoparticles. A novel protocol is developed, and the elastic modulus of individual nanospherical PE particles is computed from 'force-distance' mapping curves of AFM. Hemispherical tungsten (W) tip was fabricated from focused ion beam and used as an indenter to measure the mechanical properties. It is found that the nano sized PE particles have higher elastic modulus (E = 1.2–1.4 GPa) compared to the bulk or macro sized PE (E = 0.6–0.7 GPa). The results corroborate the robustness of our experiments, since, the analogous results for macro sized particles match well with the literature.


2016 ◽  
Vol 112 ◽  
pp. 37-41 ◽  
Author(s):  
Yun-Jiang Wang ◽  
M.Q. Jiang ◽  
Z.L. Tian ◽  
L.H. Dai

Sign in / Sign up

Export Citation Format

Share Document