Experimental Study Of Magnesium Alloy Damping Capacities

Based on micro-theory of metal mechanical property and the existing damping theory,With the two factors alloy elements content and strain amplitude when the material was in the linearity stage as the cut-in point,this paper studied the magnesium alloys mechanism on damping capacities.First, the author introduced the dislocation of the proliferation theory into the theoretical study of the materials damping, analyzed the length variety of the crystal gain and sub-crystal gain of magnesium alloy materials during the strain amplitude augmentation in the linearity stage of the material deformation, then based on G-L model author derived the mathematical model that the damping variety along with the strain amplitude augment in the linearity strain stage of the magnesium alloys, studied magnesium alloy damping mechanism theoretically. That proved the magnesium alloy material has the advantages of high damping capacities.Secondly, according to the conclusion of theoretical study, the author designed a metal material damping testing system, including choosing each component and writing the analysis software based on LabVIEW7.1;then through practical experimentation the author studied the damping capability of shape changed magnesium alloys,aluminum alloy and 45# steel , gained valuable testing data, proved that the magnesium alloy has the advantages of high damping capacities in experimental. At the same time analyzed the differences of damping properties among different forms of magnesium alloy.Combined with theoretical study and practical experimentation, the author systematic studied the magnesium alloys mechanism on damping capacities. The conclusions of the study are as follows:(1)As the strain amplitude increasing, it showed that the damping capacities can be divided into four stage : resonated damping during dislocation elastic deformation, static hysteresis damping during dislocation break loose pinning(slip breeding),dislocation line entwisted,the slip band generated.(2)The alloying element's content and distribution influenced the crystal dimension and the nailing condition of the dislocation line, sequentially influenced the dislocation's amount and it's equilibrium stage, consequently influenced the characteristic parameters and critical strain of each stage(εa,εb,εc) then the growth velocity of the damping capacities of last three stages.