Numerical Simulation Of Hot Torsion And Compression Of Porous Molybdenum

As we all know, porous Molybdenum has many specialities,such as resisting high temperature,excellence mechanism and galvanothermy.Nowaday,it has become an indispensability material in industry,and is been used in many fields. In the world,,it is conventional to manufacture the semi-manufactured good of Mo by use of power,and its density is only 9.77 g/cm~3 (in fact,the ideal density is 10.22g/cm~3) Recently,along with the development of hi-tech,Mo is been used in more and more fields,for example,in military industry,many characters is always been used such as granularity,relative density, intension and extention rate and so on. Therefore,it is very exigent for researchers to enchance the dense of Mo.The deformation of pressure-torsion is that a torque is exerted through the initiative rubbing effect in its lateral section, urging the deformable body to have the axial compression and the tangential shear deformation special plastic deformation craft with loading pressure in the highly direction of the deformable body. It is one kind of compound loading deformable ways, the technical essence lies in controlling contact friction force and the deformable body interior shear intensity, thus the harmful friction is turned between the deformable body and the mold to the beneficial function.In this article,the process changes the deformable body internal stress and strain condition with big shear strain quantity, improves in the tradition shaping some technical deficiencies. On the one hand guaranteeing reducing normal stress depression, enhancing the non-dense ability; On the other hand causing the material to have the big plastic deformation, improving material tissues, obtaining the submicron even nanometer bulk materials.Besides, by combining the method of the numerical simulation and the hypothesized orthogonal experiment, the researchers would add detailed research to the forming process of compression and torsion to porous Mo. The utilization of the plastic finite element method to simulate the forming process of compression and torsion that could reflect reasonably the influence of such technical parameters as different ratio of height and diameter, temperature, extrusion speed, friction factor, angle of torsion speed and so on upon the forming process of porous Mo. Through the analysis of the use of hypothesized orthogonal experiment, we find that in the process of forming, the compression pays a more important role than torsion,however, compression may make material more tighten,but torsion may make material more symmetrical. Additionally, through the hypothesized orthogonal experiment,we also find that there is a set of data that may make the relative density most symmetrical. Which are as follows: the ratio of height and diameter is 0.5, the friction factor is 0.5, the angle of torsion speed is 0.15rad/s, and the temperature is 425℃, at last the extrusion speed is 1mm/s. Thus, on the basic of the data,we have an experiment about the compression and torsion, ,which is very important in the application and product of Mo.