| With the improvement of people's consciousness of environmental prote ction,Magnesium alloy will be widely used in electronic,aviation automobile and communications industries as a green lightweight engineering material.Therefore,a growing number of researchers focus on the welding technology of magnesium alloys.Today,the researchers have achieved the remarkable production in the research of welding technology of magnesium alloys.With favorable advantages such as high welding speed,small heat input,the laser welding is the primary method of magnesium alloy welding.However,due to the complexity of laser welding process and metallographic transformation as well as uncertain factors in the welding process,it is particularly difficult for the experiments.However,with the high-speed development of the computer technology,the microstructure of magnesium alloy laser welding joint is analyzed by computer simulation.This method also has a good theoretical guidance for industrial production,which has gradually become a research hotspot.Basing on SYSWELD software,the phase transformation of AZ31 magnesium alloy laser welding joint is investigated by finite element simulation.The effect of process parameters,including welding speed and welding power,on the microstructure of the welded joint(including heat affected zone,the fusion zone and weld metal)as well as the size and shape of the primary phase is systematically analysed.The ratio of laser power and welding speed is defined as the welding heat input(welding line energy).With the changing of the welding heat input,the formation of weld,joint morphology,microstructure and property are also changed.At the same time,the laser welding experiments are carried out with the welding process parameters that is used in computer simulation.By contrasting the result of simulation with experimental data,the results show that:1?The finite element model based on SYSWELD finite element software is established,and the research on the microstructure transformation of the welded joints is realized based on the reasonable selection parameters and the effective simplification2?With the increasing of heat input,The grain and precipitated of welding joints gradually grow up.And the average grain size of welding heat affected zone also grow up with the increasing of heat input.3?By analyzing the results of numerical simulation,When the welding heat input is(14?20)J·mm-1,the property of weld metal is very good and the chemical composition is homogenous.4?Compared with the results of simulation and experiment,the experimental results is agree well with the results of simulation,which is verified the model is reliable and practical.Therefore,the numerical simulation results can be regarded as the theoretical basis for the study of the microstructure analysis and industrial production.The results show that the simulation results agree well with the experimental results,which validated the accuracy of this model.Therefore,it has guide meaning to the practical engineering applications and a certain reference value and significance for phase transformation of magnesium alloy laser welding joint with numerical simulation. |
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