Study On Process And Properties Of Laser Induced Arc Tailor Welded Aluminum Alloy

The tailor welded blanks(TWBs)technology was an advanced body manufacturing technology,which including the processes of welding and stamping forming.Aluminum alloy TWBs technology had the advantages of light weight structure and light weight materials,and it was a lightweight method with more promising applications.At present,steel TWBs have been widely used in the body manufacturing process,while there were still huge challenges in the application of aluminum TWBs.The insufficient formability after welded was an urgent problem needed to be solved in the preparation of aluminum TWBs.Pulsed laser induced arc welding technology had unique advantages in aluminum alloy welding because it combined the advantages of laser welding and arc welding.The pulsed laser-induced arc welding could improve the quality of joints,and the formability of TWBs,because the laser-induced arc heat sources was controllable in time and space.Therefore,the laser-induced arc TWBs technology was highly prospective and practical.This paper welded 1.5 mm 5754-5754,5083-5083,6061-6061,5754-5083,5754-6061,and 5083-6061 aluminum alloys by using the pulsed laser induced arc welding technology.The DIC system,anode micro-film and other technologies were used to study the microstructure and properties.The Erichsen cupping test was used to study the effect of stamping direction and pulse laser parameters on the formability of aluminum alloy TWBs.What’s more,the impact and improvement mechanism of the joint collapse on the tensile properties and formability of the aluminum alloy TWBs was revealed through the analysis of the force of the aluminum TWBs in the static stretching process and the forming process.The results showed that the front of the joints was smooth and tidy when laser-induced arc welding aluminum alloys,and there are obvious fish scales on the front.Laser induced arc welded joints had smaller collapse,narrower heat affected zone,finer grains and better tensile properties compared with arc welded joints.With the increased of laser power,the inconsistent collapse of the 5083-6061 joint gradually decreased,and the tensile strength increased first and then decreased.The tensile strength of joint reached its maximum when the laser power was 445 W.The tensile properties of the similar joints were stronger than those of dissimilar joints.The tensile properties of the same series joints were stronger than those of different series joints among the dissimilar joints.The grains of joints had obvious divisions.Columnar crystals were near the fusion line,while equiaxed crystals were at the center of joints.Similar to the tensile properties,the formability of the similar TWBs was stronger than that of dissimilar TWBs,the formability of the same series TWBs was stronger than that of different series TWBs among the dissimilar TWBs.The pulse laser parameters and the stamping direction had great influence on the formability of the laser-induced arc TWBs.The formability of TWBs was stronger when punching in the front.The formability of TWBs increased first and then decreased with the increased of pulse frequency and spot overlap rate.The formability of TWBs was the best when the pulse frequency was 42 Hz,the pulse width was 2.5 ms and the spot overlap rate was-16%.Laser induced arc TWBs had higher forming performance indexes and stronger formability,compared with the arc TWBs.The changes of tensile properties and formability of aluminum alloy TWBs were related to the evolution of the collapse of joints.The laser-induced arc heat source could improve the collapse and inconsistent collapse effectively of aluminum TWBs,and improve the tensile properties and formability of the aluminum alloy TWBs.