Atomistic investigation of diffusion welding of dissimilar materials through molecular dynamics simulation

Molecular dynamics simulation of diffusion welding between aluminum and nickel has been performed and the tensile behavior of the as-welded material has been examined. Two slabs Al-Ni are being contacted directly to introduce diffusion between the two with certain parameters. Diffusion welding was performed at a temperature of 500 K, at the pressure of 10 MPa in the x-direction, and a holding time of 200 ps. The tensile test is performed at a strain value of 2.64e9/s. The results have shown that the displacement of atoms during diffusion welding significantly occurs from the beginning until it reaches about 10 ps. However, the movement of atoms experiencing a plateau stage and less atomic exchange is occurring afterward. nickel slab that has a better strength was able to maintain its fcc crystalline structure during diffusion welding and tensile test than aluminum which has lower strength. The higher melting point of Ni promoting better resistance in the interface to be deformed, while the lower melting point of Al has been promoting better bonding between the two that is promoted by the defects that occur at the interface. During the tensile test, the lower strength of Al made it randomly deformed and crack seems to occur. However, failure of the diffusion-welded Al-Ni has occurred around the interface. The ultimate tensile strength of the diffusion-welded Al-Ni reaches up to 4.166 GPa at a strain value of 0.07128.