The Research Of Mechanical Performance In Ti6Al4V Porous Structure Based On Selective Laser Melting

As a kind of functional material,the porous structure has the advantages of light weight,high specific strength,damping,sound absorption and noise reduction,heat insulation and other excellent properties,and is widely used in aviation,aerospace,automotive,mold,medical and other fields.Selective laser melting(SLM)is a new additive manufacturing technology.Unlike the traditional manufacturing,SLM is able to manufacture parts with complex internal structures,allowing us a higher degree of freedom in design,consequently leading to a cut-down in design period.In short,the SLM technology is an excellent approach for manufacturing porous structure.In this thesis,the porous lattice structure of a diamond cell is processed by SLM.The effect of cell structure,cell size and rod diameter on the mechanical properties of diamond cell is studied.The main contents and conclusions are as follows:(1)Manufacture the porous lattice structure with different cell sizes and rod diameters by SLM,then conduct the static compression test and get the static stress-strain curve.The curve can be divided into four stages: elastic deformation stage,plastic stage,fluctuation stage and crushing dense solid stage.The curve shows that when the rod diameter of the porous structure with the same cell size increases,the compressive strength and compressive modulus increase;with the same rod diameter,the smaller the unit cell,the higher strength and compressive modulus of the porous structure can be obtained.(2)Conduct the SHPB(Split Hopkinson Pressure Bar)experiment to test the dynamic performance of the porous structure and get the dynamic stress-strain curve.It can be found that the dynamic stress-strain curve and the static stress-strain curve are similar and it has a certain strain rate effect.On top of that,when the rod diameter of the porous structure with the same cell size increases,its elastic modulus and strength increase,and its shaping stage is less and less obvious.When the cell size of the porous structure with the same rod diameter decreases,its elastic modulus and strength will increase.(3)According to the static and dynamic stress-strain curve of porous structure,the energy absorption characteristics are studied,and the relation between rod diameter and energy absorption is obtained.The energy absorbed by porous structure increases with the increase of rod diameter.