Temperature-mediated fabrication, stress-induced crystallization and transformation: atomistic simulations of additively manufactured amorphous Cu pillars

Abstract

Additive manufacturing (AM) is an emerging and promising technology. In this manuscript, an attempt is made to simulate an AM process via molecular dynamics simulations. Amorphous Cu pillars are built by bundling melting Cu wires parallelly one by one, with a particular temperature-controlling procedure through the use of ‘mediate temperature’. Thus, the volume fraction of the amorphous phase becomes adjustable. Uniaxial tests are conducted on the pillars after free relaxation. The mediate temperature is found to play a profound role in atomic arrangement, which governs the volume fractions of amorphous and crystalline phases. The results obtained also show that crystallization prevails when the pillar is subjected to an external tension. Furthermore, such a stress-induced crystallization serves as the dominant plastic mechanism instead of dislocation, and a vibrating uniaxial loading is found to accelerate the transformation from an amorphous to a crystalline phase, compared with a monotonic tension.

Molecular dynamics simulation of solidification epitaxial growth in a nanoscale molten pool

“…At present, due to the complexity of molten pool solidification, the MD simulation of molten pool solidification has been simplified to a rapid directional solidification model to predict the evolution of the microstructure. 14–19 For example, Mahata et al 16 reproduced the directional solidification process of Al-11 at% Cu alloys, and discussed the influence of the orientation of the solidification structure on the mechanical properties of such alloys in their research. Bahramyan et al 19 utilized MD to study the nucleation process and the microstructure of the solidification of the TWIP stainless steel bath during the laser powder bed fusion (LPBF) process.…”

“…At present, due to the complexity of molten pool solidication, the MD simulation of molten pool solidication has been simplied to a rapid directional solidication model to predict the evolution of the microstructure. [14][15][16][17][18][19] For example, Mahata et al 16 reproduced the directional solidication process of Al-11 at% Cu alloys, and discussed the inuence of the orientation of the solidication structure on the mechanical properties of such alloys in their research.…”

Plastic Softening Induced by High-Frequency Vibrations Accompanying Uniaxial Tension in Aluminum

“…The MD simulation is a good auxiliary research tool to investigate the evolution of atomic arrangements and dislocation configurations at atomic scale [ 24 , 25 , 26 , 27 , 28 ]. It can overcome the limitations of experimental conditions and exhibit atoms motion trajectories.…”