Finite element modeling of residual stresses in the diffusion bonding joints of TC4/QA110-3-1.5

The numerical simulation of residual stresses in the diffusion bonding joints of TC4/QA110-3-1.5 and TC4/Ni/QA110-3-1.5 is carried out by ANSYS. The σ_y,max impairing the joint strength appears in the narrow region between the intermetallic compounds and the TC4 side. With closing the center axis, the tensile stresses rapidly minish and gradually transform into compress stresses. So, it becomes a weak region of the joint. But the stress distribution is comparatively relaxative when using Ni as interlayer. The maximal residual stress appears on the intermetallic compounds of NiTi and Ni₃Ti between Ni interlayer and TC4, correspondingly, the joint residual stress increases with the interlayer thickness increasing.