Rare Earth Elements Of Sc, Nd Al-mg Alloy Microstructure And Mechanical Properties Of Impact

Using tensile test at room temperature, hardness measurement, electrical resistance test at room temperature, optical microscopy(OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the mechanical and electric properties and the microstructure of Al-Mg alloys at the state of casting, homogenization, hot-rolling,cold-rolling and annealling were studied. These were also analysed and explained in theory. The results show that:The first, the addition of minor Sc and Nd respectively or meanwhile can lead to increase the level of Al-Mg alloy tensile strength at the state of cold-rolling. The tensile strength of the cold-rolled alloy is improved by 14 Mpa when adding respectively 0.2%Nd, by 29 Mpa when adding respectively 0.2%Sc, and by 55 Mpa when adding meanwhile 0.2%Nd and 0.2%Sc.The second, the addition of minor Sc and Nd leads to refine the grain of as-cast microstructure in Al-Mg alloys. The fine grains in the alloys added Sc are better than ones in the alloys added Nd. The effect of refinement when adding Sc and Nd with a compound form are best.The third, the alloys recrystallization behavior when just addingNd is not very obviously inhibited. Addding Sc respectively or adding compositely Sc and Nd will inhibit recrystallization, and the recrystallization temperature is improved by 40℃.The fourth, in Al-Mg-Sc-Nd alloy, precipitates Al₃(Sc, Nd) as refined particles and nano-disperesed ones, they play a dominant role on pinning the grain boundary, leading to improve the recrystallization temperature.The fifth, the recrystallization was evidently restrained when adding Sc and Nd with a compound form. So these make the second-phase precipitated enough, and make peak values of specific conductance to the top.