Microstructure And Properties Of Tungsten Inert Gas Welding Joint Of Aluminum Foam

With the development of science and technology,conventional materials have been far from meeting the requirements of human beings in structural design,and the emergence of foam aluminum has opened up new ideas for human beings.Aluminum foam has begun to be used in aerospace,machinery manufacturing,biomedicine and automotive manufacturing.Since it is difficult to directly prepare larger foam aluminum plates,it is very important to study the process of welding aluminum foam.In this paper,tungsten argon arc welding is selected to connect aluminum foam,ANSYS software is used to simulate the welding process of foam aluminum tungsten argon arc welding,and the research method of combining experiments and simulations is used to provide the necessary welding experimental research basis for the wide application of aluminum foam.Tungsten inert gas welding without intermediate layer of foam aluminum plate,by changing the size of the welding current to connect the foam aluminum plate to obtain a variety of welding joints,welding currents:80 A,100 A,120 A and 140 A.The macroscopic morphology,microstructure,element distribution and bending strength of weld welds of welded joints are compared and analyzed.The results show that the tungsten argon arc welding welded aluminum foam is feasible,the welded joint is composed ofα-Al matrix,Al Si co-crystal and Ca Al₂Si₂ compound,forming a metallurgical combination,the flexural strength of all welded joints is higher than that of foam aluminum base,when the welding current is 140 A,the bending strength of the joint is the highest,14.1 MPa.The simulation calculation results are consistent with the actual experimental results,as the welding current increases,the weld width and depth increase,and the weld formability of the weld joint is the best when the welding current is 120 A.Tungsten argon arc welding welded with an intermediate layer of foam aluminum plate,with Al Si alloy as the middle layer,by changing the size of the welding current to connect the foam aluminum plate to obtain a variety of welding joints,welding current:80 A,100 A,120A and 140 A.The macroscopic morphology,microstructure,element distribution and bending strength of weld welds of welded joints are compared and analyzed.The results show that the middle layer improves the collapse phenomenon of aluminum foam and improves the weld formability of the welded joint of aluminum foam.With the increase of the welding current,the larger the grain size in the weld area,the white diffuse particles distributed in theα-Al matrix gradually disappear,the Al-Si co-crystals between the grains become smaller and smaller,and the grain boundaries are clearer.When the welding current is 140 A,the joint has the highest flexural strength of 14.9 MPa,which is 2.3 times that of the foam aluminum base.Compared with the aluminum foam welding model without an intermediate layer,under the same current,the temperature distribution range of the aluminum foam welding model with the intermediate layer is narrower,the isotherm is denser,the simulated melt depth and melt width are smaller,the temperature peak of the thermal cycle curve is higher,and the weld seam formability of the welded joint is the best when the welding current is 140 A.