A comparison of the effect of different heat treatment processes on laser-welded NiTinol sheets

Abstract

In this work, an attempt is made to compare the weld properties obtained through three different post-weld heat treatment (PWHT) methods, viz. water quenching, normalizing and laser processing. Butt joint was made between two NiTinol sheets of thickness 1 mm using ytterbium: yttrium aluminum garnet (Yb: YAG) laser welding process. Phase transformation temperatures, microhardness, tensile strength and corrosion resistance of the weld were compared with PWHT samples, and it was observed that PWHT resulted in significant variation in the phase transformation temperatures, microhardness, tensile strength and corrosion resistance. Concerning phase transformation temperatures, laser processing relatively resulted in minor deviation than the water-quenched and normalized samples. Concerning corrosion resistance and tensile strength, water-quenched samples had better properties than the normalized and laser-processed samples.