TY - JOUR
T1 - Mixing behavior of Ti–Al interface during the ultrasonic welding process and its welding strength
T2 - Molecular dynamics study
AU - Moon, Sunil
AU - Paek, Jae Ho
AU - Jang, Yong Hoon
AU - Kang, Keonwook
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2024/2/15
Y1 - 2024/2/15
N2 - In this study, we conducted molecular dynamics simulations to investigate the mechanical mixing and deformation behavior of hcp Ti/fcc Al bimetal formed by ultrasonic welding (UW). To analyze the effect of the interface shape, we considered sixteen sinusoidal interfaces of various heights and spatial periods along with the flat interface. Mechanical mixing between Ti and Al occurs mainly in the vibrational loading direction, while it is suppressed in the interface-normal direction, as the loading direction lies within the slip planes of both the hcp and fcc structures. The degree of mechanical mixing depended on the shape of the interface. According to the simulation results, mechanical mixing becomes active as the sinusoidal height increases, and the spatial period decreases because of the enlarged interface areas. During the bonding process, phase transformation is observed at the sinusoidal interface; hcp Ti is converted to fcc Ti as misfit dislocations formed at the interface glide as Shockley partials on the slip plane owing to the applied vibrational loading. A simple shear test was performed to analyze the welding strength. Although sinusoidal Ti/Al interfaces can have a welding strength that is higher than that of a flat interface, we found that the welding strength was not closely related to the degree of mechanical mixing. Rather, the welding strength was affected by the interaction between a wall of misfit dislocations, stacking fault tetrahedra, and lattice dislocations generated near the interface during the UW process.
AB - In this study, we conducted molecular dynamics simulations to investigate the mechanical mixing and deformation behavior of hcp Ti/fcc Al bimetal formed by ultrasonic welding (UW). To analyze the effect of the interface shape, we considered sixteen sinusoidal interfaces of various heights and spatial periods along with the flat interface. Mechanical mixing between Ti and Al occurs mainly in the vibrational loading direction, while it is suppressed in the interface-normal direction, as the loading direction lies within the slip planes of both the hcp and fcc structures. The degree of mechanical mixing depended on the shape of the interface. According to the simulation results, mechanical mixing becomes active as the sinusoidal height increases, and the spatial period decreases because of the enlarged interface areas. During the bonding process, phase transformation is observed at the sinusoidal interface; hcp Ti is converted to fcc Ti as misfit dislocations formed at the interface glide as Shockley partials on the slip plane owing to the applied vibrational loading. A simple shear test was performed to analyze the welding strength. Although sinusoidal Ti/Al interfaces can have a welding strength that is higher than that of a flat interface, we found that the welding strength was not closely related to the degree of mechanical mixing. Rather, the welding strength was affected by the interaction between a wall of misfit dislocations, stacking fault tetrahedra, and lattice dislocations generated near the interface during the UW process.
KW - Aluminium
KW - Dissimilar metal bonding
KW - Molecular dynamics
KW - Titanium
KW - Ultrasonic welding
KW - Welding strength
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U2 - 10.1016/j.heliyon.2024.e25116
DO - 10.1016/j.heliyon.2024.e25116
M3 - Article
AN - SCOPUS:85183840535
SN - 2405-8440
VL - 10
JO - Heliyon
JF - Heliyon
IS - 3
M1 - e25116
ER -