Heat-assisted hole-clinching process for joining magnesium alloy and ultra-high-strength steel

Due to the limited formability of magnesium alloy and ultra-high-strength steel, joining by forming of these dissimilar materials is still a big challenge, which requires suitable manufacturing technologies. To join both of the two limited formability materials, a heat-assisted hole-clinching process was investigated using numerical method and experiment test; AZ31B was chosen as the material of the upper sheet, and the numerical model was built in the DEFORM-2D software; isothermal thermo-dynamic coupling method was used to analyze the effect of upper sheet temperature on its formability during hole-clinching using the proposed numerical model and experiment tests. Meanwhile, the stress developing during hole-clinching which causes material fractures were analyzed, and damage distribution and fracture evolution were investigated. The results showed that the heat-assisted hole-clinching process can be predicted by the proposed numerical model; the formability of magnesium increased significantly as upper sheet temperature is raised; AZ31B and 22MnB5 can be joined using a hole-clinching method with the usage of heat. The results point to the applicability of the heat-assisted hole-clinching process to the joining of two limited formability materials.