Fiber laser welding of Ti-15-3（Ti-15 V-3 Cr-3 Al-3 Sn）alloy was performed with different postwelded heat treatments comprising single and duplex aging with or without prior solution treating after welding.The effect of PWHTs on microstructure and mechanical properties of the welded joints was investigated by optical and electron microscopes

tensile and microhardness test.The results indicate that solution treating after welding can increase the tensile strength of the welded joint with the decrease of the ductility.The welded joints without solution treating presents a better combinations behavior of strength and ductility.Electron microscopy results demonstrate that basket-weave morphology and finer size ofαphase are responsible for higher ductility of welded joints without post-weld solution treatment.Precipitation of finerαphase in microstructure of the duplex aged welded joints can be observed compared with the single aged ones

so presenting the higher micro-hardness and tensile strength.