Studying on the tensile mechanical properties of butt joint of 2.5mm thick TC4 welded by fiber laser

of which research method is applying synchronous infrared thermal imaging in conventional tensile experiment

real-time according the change of temperature field of specimen in tensile experiment. Conventional tensile experiment results show that the welded joint has similar strength but of which the elongation rate just reached 59.53% of base material. The specimen temperature field test results show that: when the axial loads is below the load corresponds to the yield strength

larger yield strength area appears in the heat affected zone of welded joint

but significant plastic strain did not appear. When the load is equal to the load corresponding to yield strength

the micro plastic deformation appears before macroscopic yield point. When the load is equal to the load corresponding to tensile strength

the length of severe plastic deformation zone of joint reaches only 35% of the base metal

and the length of severe plastic deformation zone gradually increases with the stretching process.