Study On Mechanical Properties Of AlSi10Mg Lattice Structures By Selective Laser Melting

Due to its light weight,large specific strength and surface area,energy absorption and shock absorption,sound absorption and heat dissipation,and controllable morphological structure,lattice structure has a wide range of applications in aerospace,heat exchanger and medical implantation.However,the traditional manufacturing methods of reducing and equalmaterial manufacturing often have long manufacturing cycles and cannot accurately process the structures with small units and complex end faces.As a kind of additive manufacturing technology,Selective Laser Melting(SLM)can well meet the requirements of precise processing of various structures,thus becoming an ideal method for preparing lattice structures.Therefore,in order to study the mechanical properties of lattice structures prepared based on SLM technology,this project took gradient structure and uniform structure as the research objects.Through experimental methods,the mechanical behaviors of the two structures were evaluated from the aspects of structural design,tissue observation,compression performance and failure mechanism.The main research contents of this paper include:(1)CAD modeling method and triply periodic minimal surface(TPMS)method were used to design three kinds of lattice Diamond structures: rod,skeleton and sheet.Among them,the rod-shaped structure is divided into 12 lattice structures according to the rod diameter and optimization radius,while the TPMS structure is divided into uniform structure and density gradient structure.(2)The static mechanical properties of all lattice structures were studied by uniaxial compression experiment,and their static stress-strain curves were obtained.It is found that all structures show four stages of typical lattice structure,but the stress fluctuation stage of gradient structure is shown by continuous stress platform and increasing hardening.The elastic modulus,yield strength and compression strength of the rod-shaped structure show a dual dependence on the rod diameter and optimization radius.The yield strength of the TPMS skeleton structure is significantly higher than that of the flake structure,while the compression strength of the flake structure is several times better than that of the skeleton structure.Solution treatment at 200? can improve the yield strength of uniform structure,while solution treatment at 300? can significantly improve the ductility of lattice structure.(3)The situ method of image for recording and SEM observation are used to analyze fracture mechanism of all structures.It can be found that,rod structure macro performance for collapsed from the bottom to the bottom shear damage fracture with 45 ° direction change with the increase of optimum radius,leading to the damage from the support of stress concentration,joint transition to a pillar in the middle;For TPMS structures,the failure modes of uniform structures are mainly 45° oblique shear failure and "V" type two-way shear fracture,accompanied by "transfer" of shear bands to both sides,while gradient structures almost always fracture upward in the same way from the unit layers with low relative density.