Critically-Percolated, Cluster-Packed Structure in Cu–Zr Binary Bulk Metallic Glass Demonstrated by Molecular Dynamics Simulations Based on Plastic Crystal Model

2012 ◽  
Vol 53 (6) ◽  
pp. 1113-1118 ◽  
Author(s):  
Akira Takeuchi ◽  
Akihisa Inoue
2000 ◽  
Vol 644 ◽  
Author(s):  
Xi-Yong Fu ◽  
Michael L. Falk ◽  
David A. Rigney

AbstractTribological properties of bulk metallic glass Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 were studied experimentally using a pin/disk geometry without lubrication. Experimental observations were compared with 2D molecular dynamics simulations of amorphous material in sliding contact. The friction coefficient and the wear rate of bulk metallic glass (BMG) depend on normal load and test environment. The sliding of annealed BMG re-amorphizes devitrified material. A mechanically mixed layer is generated during sliding; this layer has enhanced oxygen content if the sliding is in air. The MD simulations show that atomic scale mixing occurs across the sliding interface. The growth kinetics of the mixing process scales with the square root of time. In the simulations, a low density region is generated near the sliding interface; it corresponds spatially to the softer layer detected in experiments. Subsurface displacement profiles produced by sliding and by simulation are very similar and are consistent with the flow patterns expected from a simple Navier-Stokes analysis when the stress state involves both compression and shear.


2010 ◽  
Vol 654-656 ◽  
pp. 1038-1041
Author(s):  
Akira Takeuchi ◽  
Akihisa Inoue

Molecular dynamics (MD) simulations based on a plastic crystal model (PCM) were performed for a Pd0.4Ni0.4P0.2 alloy in Metal-Metalloid (M-MLD) type of bulk metallic glass (BMG). Two kinds of clusters of cubeoctahedron capped with four half-octahedra and trigonal prism were used as initial atomic arrangements of the Pd0.4Ni0.4P0.2 alloy. Random rotations of clusters around their centers of gravity and subsequent structural relaxation vitrified the alloy. The high glass-forming ability of the Pd0.4Ni0.4P0.2 alloy is due to the critically-percolated, cluster-packed structure that is a universal feature for both M-MLD and M-M types of BMGs.


2015 ◽  
Vol 17 (19) ◽  
pp. 12894-12898 ◽  
Author(s):  
J. K. Christie

Very accurate first-principles molecular dynamics simulations of two Mg–Zn–Ca glasses, which are candidate materials for implants, have been performed. Their structure does not strongly depend on composition, and other directions for optimisation of these glasses are discussed.


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