Research Of The Effect Of Thermal Deformation On Microstructure And Properties Of Nd-Containing AZ80Mg Alloy

Magnesium alloy is the lightest metal materials in modern applicationswhich have many excellent properties were widely used in automotive,communications, aerospace and other related industries. But the magnesiumalloy also has disadvantages, low toughness, low intensity, less capable ofplastic deformation at room temperature, which has long hindered thedevelopment and application, and the addition of rare earth elements and seek areasonable process were considered to be an effective way to improve themechanical properties of magnesium alloy.In this paper the AZ80-1%Nd magnesium alloy was research by usingmetallurgical microscope analysis(OM), fracture morphology(SEM),X-ray scananalysis(XRD),tensile properties test, hardness test to study the effect of Nd andthermal deformation process on microstructure and mechanical properties of AZ80magnesium alloy which Provide a theoretical basis for the futuredevelopment processing.Adding rare earth elements1%Nd can significantly improve themicrostructure of magnesium alloy, most of neodymium combined withaluminum to produce a high melting point and high thermal stability of rareearth phase A13Nd; At the same time it can improve the tensile strength andhardness of AZ80magnesium alloy, which played a significantly role to improvestrengthen. After homogenization treatment to AZ80-1%Nd magnesium alloy ascast state it will be observed that the higher temperature and the longer heatpreservation time of homogenization treatment, the more completely β phasedissolved, but the time of heat preservation is also the time of grain growth; Inaddition, the A13Nd rare earth phase has always been in homogenization process,it was unable to dissolve into the matrix. Through the comparison of thehomogenization process, after390℃+12h treatment group is more uniformly,which as the best homogenization process for this experiment. All of the samples carries on the constant temperature compressiondeformation experiment for many times after homogenization processing, thedeformation temperature is390℃, the accumulation ofstrain of all the finalsample are1.6, divided into one-time, two-time, three-time and four-timeaverage deformations. Through the microstructure observation, found there aresome small dynamic recrystallization grains in the organization after once andtwice deformation which due to large deformation, and the tensile strength is263Mpa and268Mpa, hardness is32.6HRB and31.4HRB respectively; Andafter three-time and four-time compression deformation, the organization ofmaterials are homogeneous, The grain size also be refined and the tensilestrength reached238Mpa and243Mpa, hardness reached284HRB and27.7HRBrespectively. The sample after plastic deformation at170℃+28h aging treatment,in the organization of once and twice deformation, β phase precipitation mainlyconcentrated in the small dynamic recrystallization grain area, while in thedeformation of three-time and four-time organizations, The β phase disperseddistribution in the grain, especially after the four-time deformation, the precipitated phase has a big number and have a multi-wide distribution, play avery good dispersion strengthening effect, in the end the tensile strength andhardness reached317Mpa and41.6HRB.