| Additive Manufacturing is also called 3D printing technology.As a rapid prototyping technique,its emergence and maturing promote the production and commercialization of personalized medical implants.This is the main manifestation of this: it has the ability to personalize custom medical implants and provide a new direction for the development of tissue engineering artificial organs.However,due to the shortage of the developing time of 3D printing technology,a revolutionary change it has than the traditional process,and a lack of advanced research condition and production experience,product performance test and evaluation domain do not have a unified standard.These problems for 3D printing products before entering the market hinder the effectiveness of preclinical safety evaluation,but also restrict the development and application of the technology.Titanium and titanium alloy has a lot of advantages,well-known in the mechanical properties,corrosion resistance and biological safety performance.And it is mainly used in orthopaedic implant materials,especially in the repair of bearing parts defects of bone or joint problem in the clinical at present.This paper mainly chooses the same kind of imported Ti6Al4 V powder,after the first to print,to determine and analyze the basic properties of the recycled raw material.Then,choose the development of current of electron beam melting technology(EBM)and selective laser sintering technology(SLM)to prepare the same designed structure of the porous and density titanium alloy specimens,and analyze its physical and chemical properties and biological safety research.The first part of this paper is mainly to research the titanium alloy powder raw materials.It mainly obtains the observation of SEM morphology of the raw material powder and the X ray diffraction analysis.In addition,it also measures the particle size distribution of powder and liquid character to determine the quality of titanium alloy powder.Results show that,due to the different preparation technology,EBM process recycling has a phenomenon of clumping of powders.There is a significantdifference both the appearance of powder and the powder particle size.By contrast,SLM is more evenly and more liquid.There is no significant difference in XRD between the two materials.This topic in the second part mainly studies the physical properties of the titanium alloy specimens prepared by the SLM and EBM technology.Firstly,the porosity distribution of porous sample is measured by means of mercury injection.The results show that the pore structures are the same as the design of the porous structure near the outside.the pore structure of the design are not very different,between 55 and 60%.Then observe the micromorphological features of the specimen,and it is mainly by the mathods of scanning electron microscopy and metallographic analysis.Finally,the compressive strength of the porous sample was prepared.The results showed that there were significant differences in the microstructure of the two specimens because of the different technology.The samples produced by EBM contain a large amount of alpha phase-like or acicular,which is typical of the wei's structure.And the SLM sample has a large beta phase,the beta phase is the body centered cubic structure,which is the structure of the net basket.Compressive strength of SLM is much smaller than the BEM.This topic in the third part mainly studies the chemical properties of titanium alloy prepared by SLM and EBM technology,it mainly analyzes the content of various elements,and determines whether it coincides with the requirements of national standard GB/T 3620.1-2007.In addition,the corrosion resistance of samples prepared by these two processes is analyzed.The test results showed that the metal content of the two specimens meets the standard.But the content is slightly different.SLM has a slightly higher N content than the standard,which may lead to the occurrence of adverse hardening of the sample,which may have a slight effect on its performance.Both the content of Cu exceed the standard slightly,which will have adverse effect on the safety of sample.We should improve the quality of raw materials to overcome these problems.Through electrochemical corrosion experiment,draw the conclusion:the corrosion of titanium alloy prepared by SLM and EBM is still good,and it does not change because of the change of process.The fourth part of this paper mainly studies the biological safety of titanium alloy specimens prepared by SLM and EBM performance.Through the cell adhesion experiments to observe the cell adhesion,it shows that cells can have the normal adhesion and growth in the porous structure,which is beneficial to bone ingrowth and mechanical fixation.The biocompatibility of samples was explored through cytotoxicity tests and hemolytic tests.The results of the vitro biological evaluation experiment show that:Both cell toxicity test results of 0 ~ 1 grade,and the hemolytic phenomena were showed no significant,but the porous sample hemolysis rate is higher than the dense solid sample.In addition,selecting the Ti6Al4 V specimens of traditional process preparation as a contrast,and the Ti6Al4 V specimens prepared by SLM technology as samples,implant into New Zealand white rabbit femur to observe the influence and function of the titanium alloy implant materials for animal bone in the long-term implant cases and thus to evaluate its biocompatibility.Compare the two kinds of pathological morphology,we can get the conclusion that not matter whether it is hard tissue slices or paraffin section,both the control and sample are not seen significant differences on pathologic morphology.Through this topic research,we explore the 3D printing titanium alloy powder raw materials composition,morphology,particle size distribution of powder particles and its liquidity.Then research the physical and chemical properties and biocompatibility of the specimens prepared by SLM and EBM technology,to provide theroy basis for the safety of medical implants by 3D printing used in the body.It also helps to transfer the 3D printing titanium alloy implant materials into clinical products and further promote the development of 3D printing technology in the medical field and the application... |
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