Effects of residual stresses on microstructure and mechanical properties of AZ31/Al2024 diffusion bonded joints

In this paper, diffusion bonding of AZ31 and Al2024 alloys using Cu-Zn interlayer was investigated. Effects of cooling rates on distribution of residual stresses in the joint zone were evaluated by finite element method (FEM). Scanning electron microscope, X-ray diffraction and shear strength tests were also applied to study the microstructure and mechanical properties of joint zone. The FEM results showed that the increase of cooling rate in diffusion bonding process led to a significant rise in the residual stresses of joint zone. The FEM also indicated that the stress peak appeared at the AZ31/Cu-Zn interface which was due to the higher thermal expansion mismatch of the magnesium alloy and the interlayer. The observation of crack initiation at AZ31/Cu-Zn interface in SEM micrographs corresponded well to the FEM results. The shear strength test showed that mechanical properties of joint zone declined with the increase of cooling rate and residual stresses.

کلیدواژه ها:

finite element method ، diffusion bonding ، shear strength ، residual stress