Interfacial defects evolution of Al 6061 / SS304 electromagnetic pulse welding joints during post welding isothermal treatment

Abstract

Defects such as pores and crack are often observed at electromagnetic Pulse Welding (MPW) Al/Fe dissimilar alloys joint interface. These defects are harmful to the mechanical properties and structural integrity of the Al/Fe dissimilar alloys joints. Hereby, the formation mechanism, evolution behavior of these defects at MPW Al/Fe dissimilar alloys joint interface were systematically investigated by experimental and molecular dynamic simulation. The results indicated that the original pores at the interface due to the shrinkage of the local melting, grew and expand rapidly under the combination of temperature and stress. When heated at 150 ℃, there is annexation of the pores and passivation of the cracks. When the temperature reached 180 ℃, the pores grow severely, the cracks expanded to the radial and circumferential directions along the pores within the interface. The defects deteriorated further at 210 ℃. The MD numerical simulation was used to testify the healing and propagation of the defects.