Biological medical materials have developed very quickly this century, and the magnesium alloy as biological medical material in function is better than other metal materials. To prepare the biological medical materials and based on the Mg-Mn and Mg-Zr series alloys, the MZ1 and MZ2 alloy ingot was prepared in this paper. The compositions of MZ1 and MZ2 alloys was designed, the microstructure of the alloy ingot was analysized and the alloy compositions were optimized; The MZ1 alloy bar and MZ2 alloy sheet were prepared respectively by extrusion and rolling. The biological medical materials were prepared through given uniform annealing, extrusion and rolling processing optimizing; The mechanical properties were improved through the heat treatment; The biological medical material which meets the requirement of the mechanical properties was prepared. Main work and results were as follows:(1) As the biological medical materials, the optimization component ratio of the MZ1 and MZ2 alloys were designed through analysis of ingot microstructure and composition of alloy.(2) Effect of the casting parameters on magnesium alloy microstructure was studied; The optimal pouring temperature and cooling intensity were 700℃and 5L/min respectively; In this case, the microstructure was spherical and uniform, the grain was refined.(3) The coring segregation was relieved, the alloy element distributed homogeneously, the forming properties of the alloy ingot were improved through uniform annealing; Based on the cast microstructures growing not evidently, the thorough uniform time was shorter, the sample grain boundary compound was slender and more dispersive, the plasticity was well improved with the temperature higher through the comparison of the microstructures in different uniform system. The optimization uniform annealing parameters of MZ1 alloy were designed through researching the uniform microstructure:the temperature was 410℃and the time was 8h; The optimization uniform annealing parameters of MZ2 alloy were designed through researching the uniform microstructure:the temperature was 410℃and the time was 16h.(4) Based on the law of the effect of the extruding parameters on the bar microstructure of MZ1 alloy researched, the optimization extruding parameters of MZ1 alloy was designed: The extruding temperature was 350℃, the extrusion ratio was 10 and the extruding speed rate was 20mm/s, reduction in pass of the magnesium alloy was controlled in 10%-20%. TheΦ29mm magnesium alloy was obtained adapted to the biological medical materials(5) The study of the effect of rolling parameters on microstructures of MZ2 alloy sheet, the interpass annealing temperature was designed, from high temperature to low temperature, 380℃,350℃,320℃, respectively. The reduction in very pass was controlled in 10～20%. Under above conditions, biological medical materical sheet with 1.0mm in thick was obtained.(6) The effect of the different aging system on the microstructure of Mg-Mn and Mg-Zr alloy was studied; The optimization aging parameters were designed:(a) Mg-Mn alloy bar: The aging temperature was 175℃and the aging time was 12h; The tensile-strength of the alloy reached 270MPa and the elongation percentage reached 8.72%. (b) Mg-Zr alloy sheet: The aging temperature was 170℃and the aging time was 12h; The tensile-strength of the alloy reached 320MPa and the elongation percentage reached 19.2%.

Mg-Li alloy has wide application foreground in the field of aviation, spaceflight and 3C due to its characteristics with low density, high strength to weight ratio and high ductility and so on. But lots of problems still exist for Mg-Li alloy, such as bad heat stability, ability of oxidation resistance and corrosion resistance, which limit the further application of Mg-Li alloy. So, the key to promote the application of Mg-Li alloy is to develop a new smelting process and research the Rolling Process of Mg-Li alloy and analysis the deformation mechanism. It had become the key to extend the application of Mg-Li alloy. The method of combining experimental study and theoretical analysis is used in this thesis.Mg-Li alloy is analyzed by OM、SEM、X-Ray、EDS and tensile tests. The foundry and rolling process for Mg-Li alloy and softening mechanism in the annealing process of Mg-Li alloy are investigated in this thesis. Based on these analyses, determined the process flow of alloys preparation-rolling-heat-treatment. Moreover, the influence of Al and Ca on the microstructures and mechanical properties of Mg-Li alloy is analyzed. The main results are as following:(1) The Mg-9Li-2Zn alloy casting process was studied. Using LiCl+LiF salts as covering agent when melting the alloy could obtain good protective effect.(2) The homogenization treatment of Mg-Li alloy was studied. With solution treatment temperature increasing, the strengthening mechanisms changed from dispersion strengthening to solid solution strengthening gradually, an appropriate prolonging the homogenization treatment time properly is conducive to solid dissolved second phase particle to the grain. Under the experimental conditions, the optimum technological parameters of homogenization treatment process of Mg-9Li-2Zn alloy were as following. The solid solution treatment temperature was 250℃, and heat preservation time was 24 hours. While the best homogenization treatment temperature of Mg-9Li-2Zn-xCa alloy was 300℃and heat preservation time was 24 hours. (3) The rolling temperature and pass reduction of Mg-9Li-2Zn alloy were studied. With the increase of rolling temperature, it occurred with dynamic recrystallization, and alloy grains were refined. The optimum temperature for rolling was 200℃-300℃,and the optimum single pass reduction of cold rolling should be controlled between 20% and 30%。(4) The anneal treatment technology after rolling was studied. And anneal softening mechanism was also confirmed. Annealing could eliminate work-hardening and residual stress formed during the process of cold rolling, to improve alloy deformability. The optimum annealing temperature of Mg-9Li-2Zn was 300℃, and the time was 60min. With the rising of annealing temperature, the hardness of Mg-9Li-2Zn alloy decreased rapidly at the beginning and then kept basically the same. After heat preservation at 300℃for 60 min, the deformation rate of the alloy plate can reach 70% in the subsequent cold rolling(5) Effect of Al and Ca on microstructure and properties of Mg-9Li-2Zn alloy was studied in this paper. The addition of Ca to Mg-9Li-2Zn alloy could increase the mechanical properties of alloy at room temperature, adding 0.1mass% Ca, the tensile strength and yield strength were increased by 19.16% and 17.22% respectively, and elongation was increased by 5.88%.

In the present study, magnesium and AZ31 magnesium alloy was selected as the starting materials. The pure magnesium sheet was hot rolled at 673K. AZ31 magnesium alloy sheet was cold rolled by unidirectional synchronous rolling and unidirectional cross shear rolling. Then, the cold rolled specimens were annealed at 523K,573K,623K and 673K for 30min, respectivly. Microstructures were examined by conventional methods and microtextures were investigated by ODF and EBSD analysis. Based on the experimental results, the mechanism of formation of {0002} basal plane texture on magnesium processed by hot rolled was discussed, the evolution of deformation textures and recrysallization textures of AZ31 magnesium alloy processed by unidirectional synchronous rolling was analyzed, the evolution of deformation textures on different layers of AZ31 magnesium alloy processed by unidirectional cross shear rolled was also studied.The research results show that the dynamic recrystallization took place during hot-rolling in as-cast pure magnesium, which made the grain refinement and the uniform size of grain obtained. The hot-rolling sheet began to form {0002} basal plane texture from relative low orientation as the increase of rolling reduction gradually. The grains with the basal plane orientation had a priority to other grains to grow up at the expense of matrix grains during the dynamic recrystallization, which lead to the basal plane texture strengthened.The hot-extrusion AZ31 magnesium alloys were rolled by unidirectional synchronous rolling at room temperature. With the increase of rolling reduction, the intensity of (0117)[0772]、(1126)[2021] and (1126)[0221] texture presented the trend of increasing at the beginning, then decreasing, while the intensity of (0117)[0772]、(1126)[2021] and (1126)[0221] texture always exhibited the tendency of keeping increasing; which were combinational effect of basal plane slip, {1011} and {1012} pyramidal twinning and <c+a> pyramidal slide.The main texture component kept constant in AZ31 magnesium alloy cold-rolling sheet as the function of annealing temperature. However, the intensity of texture fell gradually. The full recrystallization temperature declined with the increase of cold-rolling reduction, which attributed to the higher strain energy in matrix crystal grain originated from larger rolling reduction lead to greater driving force of grain boundaries. Therefore, the recrystallization finished earlier.The texture intensity of different layers in synchronous hot-extrusion AZ31 magnesium alloy sheet was symmetric with center layer. After unidirectional cross sheer rolled at room temperature, the texture intensity of fast roller side was higher than that of slow roller side, which caused that the texture intensity of different layers in magnesium alloy was asymmetric with center layer. This was because the influence of rolling district caused by cross shear rolling.

Wrought magnesium has receive much attention on its excellent properties,in order to prepare the wrought magnesium with combination property,different total reduction rolling alloys were obtained by a small rolling machine with multi-pass rolling on the as-cast Mg-5wt%Zn-3wt%Nd alloy in this paper,then carrying different temperature and holding time annealing treatments on the rolling alloys.The mechanical properties of the rolling alloy and the annealed rolling alloy were investigated by the optical microscope、SEM、TEM observation and the tensile text at room temperature.The results show that:Mg-5wt%Zn-3wt%Nd can be processed for multi-pass rolling at room temperature but annealing treatment at 330℃×15min before next the pass are needed,the total reduction can reach 66%.With the increase in total reduction,rolling streamlines are formed gradually,the average grain size decreases and much twinnings are observed in many grains.Nd are found mainly in the second phase distributed at the interface;the second phase contains relatively higher Zn element.With the increasing reduction,the strength and plasticity increase accordingly.However,the strength and plasticity approach the maximum when the total reduction higher than 50%;tensile strength,yield strength and the elongation are 285MPa 279MPa 7%,respectively.Different total reduction Mg-5wt%Zn-3wt%Nd rolling magnesium alloy after annealing treatments can generate complete recrystallization at 300℃×120min and 400℃×10min,grain grow obviously at 400℃;the strength of Mg-5wt%Zn-3wt%Nd rolling magnesium with different total reduction decrease after annealing treatments,and the plasticity increase,the combination property of the alloy reach to the best after 300℃×l20min annealing treatments. The analysis show that:rolling has great influence on the combination property of Mg-5wt%Zn-3wt%Nd magnesium alloy,the average grain size decreases obviously,much twinnings are observed in the microstructure,and the alloy strengthen obviously. Fractography analysis reveals that:the fracture is mixed fracture mechanism including brittleness and toughness.Fractography of annealed alloy show that:the fracture is mixed fracture mechanism without recrystallization,and the fractography with recrystallization is toughness fracture existing lots of dimple,So the plasticity increase significantly after annealing treatments.

Plate rolling is one of the most important metal forming processes. In rolling,non-uniform spread results in non-rectangular plates,causing yield loss. So by the purpose of predicting plan view pattern, the one-pass rolling process of 3200mm heavy and plate mill was studied.In this study, first detailed summary of the development of heavy and plate mill equipment in and abroad and the status of plate rolling process. introduces a variety of analytical methods of the process of rolling, on the basis of analyzing their advantages and disadvantages, the elastic-plastic finite element method is choosed and the fundamental theory of elastic-plastic finite element method (FEM) is given.The next in this dissertation, to get the thermal crown of rolls under thermal equilibrium state, the Elastic-Plastic FEM was used to establish the model of four-high mill thermal crown by MSC.Marc software, Obtained the stability of the rolling roll thermal crown. Used finite element analysis software to construct 3-D FEM simulation solid. In the model, the thermal crown of work roll, the elastic-plastic deformation of the strip are taken into account.Then based on elastic-plastic FEM model, the effect of rolling condition on the rolls system deformation and plan view pattern had been analyzed and the qualitative rules of plan view pattern after rolling were obtained.Finally combined with the theoretical derivation and the large quantity computational cases by FEM on the production conditions of plate rolling, the prediction model of plan view pattern was obtained. Through the analysis of the computational data from FEM, the formula of the plan view curves of plate after single pass was regressed with polynomial expression. In this formula, the arithmetic product of contact length and reduction ratio was one variable, the length or width coordinate was another. This research had an important reference value for the theoretical and practical industry guidance of in-depth studying plan view pattern control and key technologies research and development

Magnesium alloy have the advantage of lightweight but the limited ability in plastic forming. The cost of sheet rolling keeps high due to the huge investment in equipment for blooming roller and the multi-rolling and annealing in the forming of sheet. Only the domestic defense industry and aerospace area can afford the cost of high-performance sheet, which is still depend on import. Since the method of extrusion blooming before rolling is a efffective way to deform the metal with poor formability, it is very important to carry on a deep research on this method. In this paper, the processes of extrusion- longitudinal rolling and extrusion- transverse rolling were investigated with the alloy of ZM21 and other two alloys with lwo and high content of Ce. With experiments of the commercial extrusion and rolling, mechanical properties test at room temperature, microstructure analysis, and the scanning electron microscopy observation for fracture morphology, the possibility of blooming extrusion followed by rolling for magnesium alloy is proved. The effects of alloy content, rolling direction and rolling reduction on the mircostructure and mechannical propertise and their anisotropy were investigated. Test results show that:A refine uniform structure of recrystallization can be obtained by extrusion blooming at the temperature of 420℃, with a extrusion ratio of 175 and a homogenization treatment of 420℃×12h. With the increase of Ce content, the grain becomes smaller in size. The grain size of ME0 (the Ce-free alloy (ZM21) )is about 21μm, and for Low Ce (0.19%) alloy ME3 the size is about 18um, for high-Ce (0.57%) alloy ME7 is about 13um; Tensile strength: the strength of ME0 in 0°and 90°direction are close to each orther, between 245MPa and 250MPa, 10MPa higher than 45°direction. The strength increases more than 10MPa in all directions and decalines in relative differences for the alloy with Ce addition, with the except that the ME7 only has little increasing in 0°direction. Yield strength: except that the strength of ME3 in 0°direction and that of 90°in ME7 are close 150MPa, other strength of the alloys in different directions are all between 135-140MPa. Elongation: ME0 in 0°and 90°direction are about 10%, 45°direction for the 22%..With the addition of Ce, the elongation of all directions has a improvement of 5-10% while the 90°direction of ME7 dropped to 12%. Comparing the IPA indexes of different alloys shows, ME3 is the best for a good combination of strength and elongation IPA, with the IPA of tensile strength is 1.82%, the IPA of yield strength is 8.1%, and the IPA of elongation is 23%. Among the three alloy with different Ce content, the ME7 has relative high IPA. The ME0 and ME3 alloy have a better exhibition of be identical in all directions.The fibrous structure from extrusion is maintained in the ME0 alloys after transverse rolling or longitudinal rolling at reduction of 31.0%, while the structure become equiaxed in view of both sideway and endways at reduction of 44.8%. Grain size after rolling are mainly in the 10-20um. The strength of ME0 alloy improves with the increase of deformation, sepecialy for the yield strength. By longitudinal rolling, the tensile strength and yield strength of the direction of 90°are the highest and that of 0°direction is the lowest, with a difference of about 40MPa. The elongation increases firstly and then decreases with the increase of deformation, while that of 45°direction is always about 5% higher than the other two directions. By transverse rolling, the strength in the 90°direction is slightly higher than others with about 40MPa at small amount of deformation. When the deformation to 44.8%, the tensile strength is about 280MPa, and the yield strength is around 220MPa, with the difference of that in different directions is not more than 10MPa. The elongation of 90°direction is as higher as bouble of the direction of 0°in the low deformation, while the elongations in all directions are basically equivalent when the deformation achieve to 45%. The transverse rolling is better than the longitudinal rolling to keep the isotropy of mechanical propertiseAfter longitudinal rolling and transverse rolling, ME3 alloy need to a deformation of over 44.8% so that to get fully equiaxed structure, with very fine grains of size mainly about 5μm. The strength increases firstly with the longitudinal rolling and transverse rolling deformation increasing, and then when the deformation is over 44.8% decreases. The elongation for longitudinal rolling has a strong consistency, and the elongation of the three directions is all in 17% to 18% when the deformation is 65.5%. The elongation of transverse rolling in 45°direction is always the highest and increases slowly from 12% to 16% with the increasing of deformation, while that of 90°direction is the lowest when the deformation is smaller than 44.8% and it will keep up with that of the 45°direction when the deformation is 65.5%. The longitudinal rolling is better than the transverse rolling to keep the isotropy of mechanical propertise of ME3.With the deformation increasing of longitudinal rolling to ME7 alloy, the tensile strength changes in the scope of 270-310MPa, the yield strength improves obviously from 180 MPa to 230MPa when the deformation changes from 44.8% to 65.5%, the elongation weakens seriously especially for the 0°direction. After transverse rolling, the average strength of all direction is 70MPa higher than that of as extruded, and the strength increases littile as the dieformation increases. The elongaton of the rolled sheet decreases heavily, almost as half as that of as extruded salb in the 90°direction。Comparison with transverse rolling and longitudinal rolling, it can be found that transverse rolling is good for getting more uniform micro-structure of 90°and 0°direction, especially when the transverse rolling deformation is low, that is helpful to control the anisotropy. In contrast, the large deformation for longitudinal rolling is good for make all mechanical propertise coincident in different directions.By Comparing of IPA for rolled sheet of three alloys; we can find that the anisotropy of ME7 plates was significantly serious than the other two alloys, ME0 and ME3, their sheet are not so different in IPA. ME0 alloy is suitable to transverse rolled. When the reduction achieved in more than 44.8% the mechanical properties in different directions get a strong consistency, while the tensile strength of the three directions is all between 258Mpa and 295MPa, and the yield strength is in 173Mpa-203Mpa, and the elongation is in 11.2% -22%. ME3 alloy is suitable to longitudinal rolled, with the reduction increasing the consistency of elongation significantly improved and strength consistency is good too. When the reduction is 66.5%, tensile strength is between 244MPa and 267MPa, yield strength is between 135MPa and 138MPa, elongation is between 17.3% and 18.1%.

The 5083 aluminum alloy belongs to the series of Al-Mg which is a deformation alloy and can not be strengthened by heat treating. It is widely used in shipbuilding industry. In this paper, the behavior of 5083 aluminum alloy during hot compression deformation have been studied by means of the isothermal compression simulation test. The effect of different rolling and stabilizing treatment conditions on the microstructure, mechanical properties, and corrosion properties of the 5083 aluminum alloy sheet is discussed by a series of tests and studies. Such as orthogonal experimental design, testing mechanical properties test, scanning electronic microscope (SEM), energy dispersion spectrum (EDS), metallographic microscopy, intergranular corrosion test and exfoliation corrosion test, polarization curve determination and so on. The optimum 5083 alloying component content is obtained according to the above experimental result.The optimization of production process of the 5083 H116 alloy sheet is improved. The results show that:①The stress raise with the increase of strain rate at the same compression temperature, which show 5083 aluminum alloy is positive strain rate sensitivity material, the stress raise with the reduction of compression temperature at the same strain rate. Deforming degree has little effect on the stress at the same strain rate and the same compression temperature.②The anti-corrosion properties of 5083 alloy have great effect on cold deformation and stabilizing treatment process, the intergranular corrosion and exfoliation corrosion of the 5083 H116 alloy sheets tend to raise with the increase of cold deformation and the reduction of stabilizing treatment temperature. The mechanics of intergranular corrosion and exfoliation corrosion of the alloy were analyzed.③The poor corrosion resistance results from a continuous network ofβ-phase and along the planes of localized deformation in alloy after cold-rolled and stabilizing annealing below130℃. The high corrosion resistance of the cold-rolled alloy stabilizing annealing at 220～250℃is relate to discontinuousβ-phase precipitation uniformly distribute throughout the structure in a globular form. The poor corrosion resistance of cold-rolled alloy stabilizing annealing at higher temperature is attained because of a continuous network ofβ-phase precipitates at boundaries.④Through 5083 alloy component proportion experiment,compare the influence on mechanical properties and anti-corrosive performance of 5083 H116 alloy sheets with different percentage of the element content in order to confirm the best component matching of 5083 alloy. The optimum cold deformation, annealing temperature and time were presented.

Electromagnetic continuous cast(EMC) has many advantages such as:smooth ingot surface,compact,homogeneous and higher casting velocity.Magnesium alloys are the lightest metallic structural materials and they are very attractive in automobile and aerospace industries. The EMC magnesium alloy crystal has much finer and more uniform than normal casted billet. In this paper,hot plastic deformation process of the EMC AZ31 and AZ61 alloy has been studied.And the microstructure,mechanical properties and fracture morphology has been researched before and after deformation.The results as follows:(1) As-forged AZ31 alloy has much refined grains and composition is more uniform, homogeneous and the material is more densified.The hardness of deformed AZ31 alloy was significantly improved.The hardness of as-forged alloy changed forging-direction once and twice is 55 and 63,which were respectively enhanced by 22%and 40%,compared with that of as-cast samples.The fracture morphology has changed,intergranular fracture at high forging temperature,while transgranular fracture at room forging temperature.(2) Rolled AZ31 alloy has fine grains and small uniform microstructure with no obvious deformation direction.There are a large number of deformation twins in grains,trending into the rolling direction.As-rolled AZ31 alloy has better mechanical properties than that of as-casted.The samples of 45°direction to rolling direction have the best mechanical properties, and its yield strength,tensile strength and elongation are respectively reached 194MPa, 383MPa and 27.7%.The fracture surface demonstrates that the rolled AZ31 alloy has characteristic of ductile fracture.(3) The hot extruded experiment results demonstrate that the extrusion processing gives rise to a strong basal texture.The grains are significantly refined and the average grain size of the localized fine grain area is 2μm.Compared with the EMC ingots,as-extruded specimens have much finer grain size and more uniform microstructure.The mechanical properties of the deformed AZ31 were improved after hot-extrusion.The yield strength,ultimate tensile strength and the reduction in cross-sectional area increased obviously with the increasing of extrusion ratio.When the extrusion ratio was 25,the yield strength,ultimate tensile strength and the reduction in cross-sectional area of as-extruded AZ31 alloy were 259MPa,357MPa and 30.5%, which were respectively enhanced by 86.33%,64.52%and 67.40%,compared with those of as-cast samples.With the increase of extrusion ratio,the grain refining effect was more significant and the microstructure was more uniform.The fracture surfaces demonstrate that the fracture mode changes from ductile-brittle fracture to ductile fracture after extrusion.(4) Yada model in MSC.superform was used to simulate the real extrusion deformation of AZ31 alloy.With the increase of extrusion ratio,the grain refining effect was more significant and the microstructure was more uniform,which consistent with the actual experimental results.

For a long time,the raw materials of JinDuiCheng Molybdenum Company production ofφ52 molybdenum billet rods usually is small particle size(≤3.5um) molybdenum powder.But there are many problems of theφ52 molybdenum billet rods which are produced by big particle size(3.5～4.5um) molybdenum powder in the forming processing,at the same time, the big size molybdenum powder has already been used abroad widespread.So it is necessary and important to study the processing of molybdenum billet rods which are produced by big size molybdenum powder.The general difference of molybdenum billet rods character such as particle size,bulk density,O elements content,grain pattern between the big size molybdenum powder rods and general powder rods are analyzed in this paper.The processing parameters of powder reduction,billets pressing and sintering are determined by a great of trials.The chemical elements and physical characters are detected and compared in order to determine the differences of molybdenum rods of the two kinds of powder.The parameters of billets pressing and sintering are adjusted according to the trial results.The performance differences of molybdenum billet rods during rolling and drawing process are compared in order to finally determine the optimum process parameters and solve the practice processing problems.

Magnesium alloys are the lightest metallic structural materials. The density of magnesium alloy is 35% lower than it of aluminum alloy. Magnesium alloys used on many fields which conclude Aerospace, automotive industry, electronic information industry, household appliances and civilian areas such as national defense industry have broad application prospects and important commercial value because of the higher strength, better electromagnetic shielding capability, better damping property and well machinability.At present, Most of magnesium alloy products are mainly obtained through the casting(including the traditional casting process and a new casting process which called semi-solid casting process ) . Magnesium alloy castings can be very complicated shape. Because of the thick crystal and composition segregation , it can not fundamentally solve the problem of brittleness and corrosion, so we can not manufacture the good performance of magnesium alloy castings. Compared with casting magnesium alloy, wrought magnesium alloy has smaller grains, less micro-empty and less segregation and more suitable for the production of large-scale structureDue to the high affinity between magnesium and oxygen, magnesium oxide generated by the structure of osteoporosis, it can not prevent internal oxidation of the metal to continue, and magnesium oxide heat of formation is very poor and causes thermal conductivity profiles in the processing of magnesium alloy easily oxidized in the combustion process. The antioxidant of magnesium alloy will decline, when the temperature of alloy higher than 350℃. So when deformation of magnesium alloy in the processing, production, stockpiling and use of the period, it should be the use of appropriate protective measures to prevent burning. General large-scale magnesium alloy parts will not be caused by burning. But during processing of magnesium alloy produced by the dust, debris and burrs due to its larger surface area, in the air after the heat caused by burning easily. If a large number of dust increase, they will be floating in the air and mixed with air to form explosive mixtures, the event of fire, explosion occurs fierce burning accident. When burning magnesium alloy dazzling light, and the flames spread fast and difficult to fight which make the production more difficult and even dangerous, hindering the magnesium alloy material further. Large-scale use of magnesium alloy in today’s, launch of the deformation of magnesium alloy combustion research, in order to find a magnesium alloy to improve the combustion of the ways to reduce the occurrence of fire on the safety profile of magnesium alloy production, stockpiling and use of very importance.Rare-earth as an effective alloying element, because of its affinity with oxygen than magnesium and oxygen affinity, because it has a better affinity with oxygen than that of magnesium, so it can be widely used in the study of flame-retardant magnesium alloy. But there are fewer researches on wrought magnesium alloy antioxidation with adding rare earth elements.In this paper, AZ31 magnesium alloy was chosen for the study with adding rare earth elements when melting. Paper researched the effect of rare earth elements content on magnesium alloy flammability and the effect of rolling process on magnesium alloy flammability. According to the research, paper has some conclusions:(1) Rare earth elements Ce and Gd can increase the ignition point of magnesium alloy obviously. The temperature is higher than that of magnesium alloy without rare earth elements in it. The ignition point of magnesium alloys changed base on the form of Ce and Gd exist in magnesium alloys. When the rare earth elements content under the solid solubility of magnesium alloy, the rare earth elements can increase the ignition point of magnesium alloy chips with the increase of their content. When the rare earth elements content equal the solid solubility of magnesium alloy, the ignition point reaches highest value. When the rare earth elements content above the solid solubility of magnesium alloy, (rare earth elements formed Al4Ce or Al2Gd) the rare earth elements can decrease the ignition point of magnesium alloy chips with the increase of their content.(2)The main reason that Ce and Gd can improve the flammability of magnesium alloy is that rare earth elements which formed solid solution in alloy. In oxidation process, this Ce and Gd formed Ce2O3 and Gd2O3 which can fill in the holes that formed by MgO. And these oxide can form a kind of dense composite oxide film with MgO. So that, it can delay combustion of magnesium alloy and raise the ignition point of magnesium alloy. But Al4Ce and Al2Gd can reduce the ignition point of magnesium alloy. It is because with forming Al4Ce or Al2Gd, in magnesium alloy can appear some areas around them where lack rare earth elements. In these areas, Ce or Gd can nont form oxides because Al4Ce or Al2Gd is thermal stability phase. So these areas will oxidize deeply and decrease the ignition point of magnesium alloy.(3)Rolling process can decrease the ignition point of magnesium alloy. After rolling, the grain boundary structure become looser and the Atomic arrangement become more disorder than before. It makes the oxide film have more channel that allow oxygen go into deeper to reacted with magnesium. Rolling process can cause grain refinement, and increase the quantity of grain boundary. So it also increase the oxidation areas, and make the ignition point of magnesium lower.