Research On The Property And Fabrication Of Biomedical Porous Ti-Based Bulk Metallic Glass Alloy Ti_65.5Fe_22.5Si₁₂

Metallic glass is one of the most potential materials in the field of biomedical material with a series of advantages,such as,high strength,low Yang's modulus,good corrosion resistance and excellent wear resistance.Ti_65.5Fe_22.5Si₁₂ bulk metallic glass,which do not consist of bio-toxic and harmful elements,such as,Ni and Be,is an excellent long-term implantable biomedical materials,with the feature of low cost,good corrosion resistance and good mechanical properties.First of all,rapid freezing technology of metallic liquids was used to figure out alloy composition leading to fabricate Ti_65.5Fe_22.5Si₁₂ metallic glass powder,in which optimizing the parameters of mechanical alloying method to obtain the best powder processing parameters.Secondly,the powder would be sintered into the bulk,in which a research on the sintering parameters of bulk metallic glass should be on the schedule for investigaing the impact of sintering temperature and stress on the feature of bulk metallic glass including phase structure,thermal stability,Yang's modulus,compressive strength and corrosion resistance.At last,the porous titanium-based metallic glass material with good corrosion resistance,the mechanical property of which matches with mechanical properties of human bone,is fabricated with the most appropriate parameters of mechanical alloys and sintering.And the results are as follows:The research on the impact of parameters which consist of the mass ratio of the ball to material,the mass ratio of big milling ball to samll milling ball and the ball milling time on the fabrication of amorphous powder in the process of fabricating the powder with the method of mechanical alloying was completed.According to the result of research,the transformation rate of crystalline powder into amorphous powder rises with the increasement of the mass ratio of the ball to material and the mass ratio of big milling ball to samll milling ball,but the stability of amorphous powder declined with the increasement of that,which leads to the rise of possibility of generation and the growing rate of intermediate phase.When the mass ratio of ball to the material is 40:1,or the mass ratio of big milling ball to small one is 2:1,some intermediate phases appear in the powder with some crystal phase still existing in the powder.And the rate of transformation of crystalline phase to amorphous phase in the powder rises with the increasement of ball grinding time.The mechanical alloying parameters for fabricating the amorphous powder are that the mass ratio of ball to the material is 20:1,and the mass ratio of big milling ball to small one is 1:2,and the ball milling speed is 300 r/min,and the ball milling time is 77 h.The impact of sintering stress and sintering temperature on th e feaure of Ti_65.5Fe_22.5Si₁₂ bulk metallic glass including compressive performance,Young's modulus and thermal stability was on the next research in the process of fabricating the bulk metallic glass with the technology of sintering plasma sintering.It turned out that the phase structure and thermal stability of bulk metallic glass did not change with variation of sintering stress,but the porosity of porous bulk metallic glass declined with the increasement of sintering loading stress,leading to more compact structure,the increasement of Young's modulus and compressive strength of bulk metallic glass.When sintering parameters include a sintering temperature of 455?,a heating rate of 40?/min and an heat holding time of 10 min,the most suitable sintering stress for the metallic glass matching with the mechanical performance of the human bones is 400 MPa.Meanwhile,the Young's modulus and compressive strength of bulk metallic glass rised with the increasement of sintering temperature leading to more compact structure at the sintering loading stress of 400 MPa.But the inner part of bulk metallic glass transformed into crystalline part as th e sintering temperature was more than 515?,which leads to the decline of corrosion resistance.Above all,when the sintering temperature is 455?,the compressive strength and Young's modulus of Ti_65.5Fe_22.5Si₁₂ bulk metallic glass matches with that of human bones,and the corrosion resistance of bulk metallic glass is superior to that of CP Ti(Commercially Pure Titanium)and Ti-6Al-4V.