Study on Finite Element Analysis and Experimental Verification on Annealing of Diffusion Bonded Mg/Al Alloys

With the rapid development of the transportation, aerospace, and defense industries, magnesium
alloys have received growing attention due to their low densities, high specific strengths, excellent
casting ability, and outstanding vibrational energy absorption. In this research, based on the theory of
thermal conduction and thermal-elastoplasticity, finite element method was applied for analyzing the
effect of annealing temperatures on residual stress in the diffusion zone of AZ31 Mg and 6061 Al
alloys. To verify the reliability of simulations, experiments on microstructure and mechanical behaviors
of diffusion zone were also investigated. Simulations on annealing of the welded specimens at 200°C,
250°C, and 300°C were conducted. Moreover, experiments such as diffusion bonding and annealing,
analysis of residual stress by X-ray diffraction, elemental analysis using an electron probe microanalyzer,
and microstructure investigation via scanning electron microscopy were performed for
further investigation of the diffusion layers. According to the results of simulations and experiments, it
can be depicted that the diffusion layers widen with increasing annealing temperatures, and the
results of the simulations are in good agreement with those of experiments. Microstructure and
elemental distribution were the most uniform and the residual stress was the least for samples
annealed at 250°C. Thus, 250°C was found to be the most appropriate annealing temperature.