Unveiling the effect of interface on torsional behavior of crystalline Al-Al₉₀Sm₁₀ metallic glass nanolaminates

ABSTRACT

Influence of configurational design of single crystal Al-Al₉₀Sm₁₀ metallic glass nanolaminates on torsion deformation behaviour of Al/Al₉₀Sm₁₀ nanolaminate (Configuration 1) and Al₉₀Sm₁₀/Al nanolaminate (Configuration 2) from a structural evolution aspect have been analysed by employing Molecular Dynamics for a torsion speed of 1/600 revolution/ps. Adaptive common neighbour (a-CNA) analysis, Dislocation extraction algorithm (DXA), atomic shear strain analysis, and Voronoi Polyhedral (VP) analysis have been carried out to reveal the structural evolution in the nanolaminates specimen subjected to torque. As a consequence of dislocation density localisation under torsional loading in Al/Al₉₀Sm₁₀ nanolaminate high atomic strain gradient is developed in the nanolaminate specimen causing torsional buckling of the Al/Al₉₀Sm₁₀ nanolaminate. The localisation of dislocation density rings induces the formation of dislocation substructure in Al/Al₉₀Sm₁₀ nanolaminate. The crystalline/amorphous interface serves as a free surface and encourages the formation of such dislocation substructure. The collective nucleation, coalescence, and growth of shear transformation zones (STZs) leading to the formation of thick shear bands on either end of Al₉₀Sm₁₀/Al nanolaminate inducing an almost homogenous atomic strain gradient across the surface of the nanolaminate specimen thereby averting torsional buckling. The C/A interface serves as a nucleation site for the generation STZs in Al₉₀Sm₁₀/Al nanolaminate. VPs such as <0, 0, 4, 6>, <0, 3, 6, 4>, <0, 3, 6, 5> <0, 2, 8, 2> have the load bearing capacity and are resistant to fragmentation under the subjugation of torsion loading.

KEYWORDS:

• Torsion
• dislocation structures
• shear bands
• crystalline-amorphous nanolaminates
• dislocation density localisation

Acknowledgements

The authors like to thank the Computer Center of NIT Rourkela for providing the High Performance Computing Facility which was essential for carrying out this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author, Dr. S. Pal, upon reasonable request.