Study On Parametric Design And Properties Of Porous Structure Formed By Selective Laser Melting

As one of the means of lightweight design,porous structure is widely used in aerospace,automobile mold,medical industry and other fields.In recent years,researchers have been exploring new methods of porous structure design,among which functional gradient porous structure has been studied,and its performance can be controlled by volume fraction gradient.Therefore,a parameterized porous structure design method is proposed in this paper,which provides a new idea for the subsequent research of more porous structures.Selective Laser Melting(SLM),as a representative additive manufacturing technology,can not only display the details of the porous structure well,but also print out better performance,so it becomes an important tool for its research.In addition,the study of lattice porous is bound to involve the selection of experimental materials,among which titanium alloy material has good performance and wide application range.Therefore,the research content of this paper will be carried out on the basis of this material.In this paper,based on the properties of Ti6Al4 V alloy and the lattice structure of adamantite crystal cells as the research object,the design method and mechanical properties of porous Ti6Al4 V alloy samples were studied by experimental means.The properties of Ti6Al4 V alloy were studied.The characteristics of Ti6Al4 V powder and the properties of forming parts determine the forming quality of subsequent dot matrix porosity.The roughness of Ti6Al4 V work piece was measured to be between3-5,and the resulting density was 4.44g/ [cm] ^3.On this basis,Ti6Al4 V tensile test was designed,and then different heat treatment methods were used to explore its mechanical properties.The experimental results showed that Ti6Al4 V elastic modulus of the experimental material reached 113 GPa,and the forming quality and strength were good.In addition,the mechanical properties before and after the phase transition of the tensile parts decreased,but the fracture elongation increased.This paper analyzes the structure characteristics of diamond prototype cell,introduces the diamond porous model with hexagonal pillar section,analyzes the macroscopic configuration of the porous structure and the geometric characteristics of the macroscopic configuration in space,and proposes a parameterized modeling method based on the characteristic points of macroscopic structure.Then,to study the intersection node of the lattice structure is the smallest unit four pole position relations,and by using mathematical method to obtain the coordinates of the feature points throughout the cell,determine the spatial geometric relationships of macrostructure,and then using Matlab software to realize parameterized modeling of porous structure,finally find out the unit cell volume fraction parameterized expression.Based on the uniaxial compression experiment,three different Ti6Al4 V alloy porous samples were selected as the research object to detect the mechanical properties of the porous samples at a compression speed of 2.0mm/s.By means of the compression failure process,the failure behavior and mechanism of porous structures with the same unit size but different volume fractions were analyzed.It is found that the porous sample has two failure behaviors: layer collapse and 45° shear.Finally,the porous sample was placed in an inert gas environment of 650℃ and kept warm for 120 minutes.Then,it was cooled with the furnace and stress-relieved annealing was carried out.Through the experimental analysis of the porous samples before and after the heat treatment,it is found that the heat treatment process has no great influence on the elastic modulus and deformation mechanism of the porous structure,but has a great influence on the mechanical properties such as ultimate strength,platform stress and energy absorption.The ultimate strength and energy absorption capacity of the two porous samples decreased,but the change of the platform stress was inconsistent.