Preparation And Properties Of Mg Containing Porous Ti-Cu Alloys Prepared By Microwave Sintering For Biomedical Applications

Ti-Cu alloys have attracted widely attentions in the surgical fields such as human hard tissue repair and implant replacement due to their excellent mechanical and antibacterial properties.However,their excessively high elastic modulus can easily cause the“stress shielding”phenomenon,and they have no biological activity.In this paper,a microwave sintering coupled with Mg space holder technique was used to prepare Mg containing porous Ti-Cu alloys to reduce the elastic modulus of the Ti-Cu alloys,and the degradation of the residual Mg was used to enhance the biological activity of alloys.The effects of sintering temperature,Cu content,Mg content of the space holder and particle size on the microstructure,compression performance,corrosion resistance,degradation performance and antibacterial property of porous Ti-Cu alloys were studied.At the same time,the antibacterial properties of Mg containing porous Ti-Cu alloys were investigated for 6 and 24 hours,and the effect of Mg content of the space holder on the cell compatibility of porous Ti-Cu alloy was studied.The results show that the porosity of Mg containing porous Ti-Cu alloys decreases with increasing sintered temperature,and the connectivity between pores increases,but the number of pores increases with the content of Mg space holder,and the pore diameter increases with the increase of Mg particle size.Increasing Cu content has little effect on the pore structure of the alloy.The alloys are mainly composed of?-Ti phase,Ti₂Cu phase,Cu₂Mg phase and Mg phase.The intensity of the diffraction peak of the Ti₂Cu phase increases with the increase of sintered temperature and Cu content.The increases of Mg content and particle size have a significant effect on the change of Cu₂Mg phase and Mg phase.The compressive strength and elastic modulus of Mg containing porous Ti-Cu alloys increase with increasing sintered temperature and Mg particle size,and gradually decrease with increasing Mg content,while the elastic modulus first increase and then decrease with the increase of Cu content,reaching the maximum value of 8.64 GPa.At the same time,the elastic modulus of all the samples varies from 3.36 to 17.88 GPa,which can avoid the“stress shielding”phenomenon.The corrosion resistance of the alloy is poor when the sintering temperature at 700°C,but the change is small ranged from 800 to 1000°C.Cu content and Mg particle size have no significant effect on the corrosion resistance of the alloys;the increase of Mg content gradually increases the corrosion potential of porous Ti-Cu alloys.The Mg containing porous Ti-Cu alloy prepared by sintered at 700°C has the largest dehydrogenation amount in SBF solution,which can reach 0.788 m L/(g·cm²),while the dehydrogenation amount of alloys prepared by other processes is only 0.011-0.041m L/(g·cm²),and bone-like apatite lacking Ca forms on the surface of the Mg containing porous Ti-Cu alloys after immersion degradation in SBF solution,indicating that the addition of Mg makes Mg containing porous Ti-Cu alloys biologically active.Microwave sintered Mg containing porous Ti-Cu alloys can achieve 99.999%antibacterial efficacy against E.coli and S.aureus for 24 hours.At 6 hours,the antibacterial rate of the sintered sample at 700°C is the highest.With the increase of Cu content and Mg particle size,the antibacterial rates of the samples increase.With the increase of Mg content,the antibacterial rates of the samples increase first and then decrease,reaching the maximum value at 15wt.%.MC3T3-E1 cell culture test finds that with the increase of culture time,the OD value of various samples increases significantly,but the same culture time,with the increase of Mg content,the OD value and cell proliferation rate of the samples decrease.Especially when the Mg content is20wt.%,a very significant decrease occurs,the fragmentation of the cells increases greatly,and the dead cell impurities increase sharply.