A molecular dynamic simulation-based study on nanoscale friction stir welding between copper and aluminium

ABSTRACTThe primary aim of this study is to enhance our understanding of friction stir welding (FSW) at the atomic level. To accomplish this, we utilised molecular dynamics simulations to examine the nanoscale fusion welding of dissimilar metals, i.e. aluminium and copper, through the FSW method. Our particular focus was on how the rotation speed of the tool affects structural changes and defect evolution during the nanoscale FSW process. Our research findings revealed that the region subjected to frictional stirring undergoes a phase change as a result of extensive plastic deformation during the FSW operation. Notably, stacking faults and similar defects were predominantly observed on the advancing side as the tool rotated and moved into the friction stir zone. Further, investigation of atomic shear strain snapshots indicated that higher rotational speeds resulted in a broader and more scattered friction stir zone, requiring a longer recovery time compared to slower rotational speeds. Additionally, the changes in atomic concentration during FSW have been studied using displacement vectors, concentration profiles and diffusion coefficient parameters. We also conducted simulation-based tensile and shear deformation tests, which revealed that higher tool rotational speeds led to enhanced material interlocking, consequently improving the mechanical strength of the FSW joints.KEYWORDS: Dissimilar materialfriction stir weldingmolecular dynamic simulationnano welding Conflicts of interestThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Authors contribution statementAll the authors are actively involved in Conceptualisation; Data curation; Formal analysis; Investigation; Methodology; Resources; Software; Supervision; Validation; Visualisation; Writing – original manuscript draft; Writing – review & editing.Data availabilityThe raw/processed data required to reproduce these findings cannot be shared at this time because it is a part of an ongoing study.Disclosure statementNo potential conflict of interest was reported by the author(s).