Thermal self-compressing bonding (TSCB) is a new solid-state bonding method pioneered by the authors.With electron beam as the non-melted heat source,previous experimental study performed on titanium alloys has proved the feasibility of TSCB.However,the thermal stress-strain process during bonding,which is of very important significance in revealing the mechanism of TSCB,was not analysed.In this paper,finite element analysis method is adopted to numerically study the thermal elasto-plastic stress-strain cycle of thermal self-compressing bonding.It is found that due to the localized heating,a non-uniform temperature distribution is formed during bonding,with the highest temperature existed on the bond interface.The expansion of high temperature materials adjacent to the bond interface are restrained by surrounding cool materials and rigid restraints,and thus an intal elasto-plastic stress-strain field is developed by itself which makes the bond interface subjected to thermal compressive action.This thermal self-compressing action combined with the high temperature on the bond interface promotes the atom diffusion across the bond interface to produce solid-state joints.Due to the relatively large plastic deformation,rigid restraint TSCB obtains sound joints in relatively short time compared to diffusion bonding.