| Titanium alloys and zirconia are widely used in aerospace,medical implants,and other fields.The composite material of titanium and zirconia has the characteristics of high strength and hardness,excellent wear resistance and high temperature performance.However,they do not wet each other,and the traditional manufacturing method is difficult to achieve an effective combination.Selective laser melting(SLM)technology has the characteristics of high energy density,high accuracy,high speed and can be customized.It is an ideal process for fabricating titanium based zirconia composites.This subject use the method of ultrasonic vibration for pre-mixing and continuous mixing with a powder mixer was usedto prepare two kinds of powders with titanium alloy and zirconia mass ratios of 100:3 and 100:10,TC4-3nYSZ and TC4-10nYSZ.Nano-sized zirconia powder is evenly distributed on the surface of micro-scale TC4(Ti-6A1-4V)powder balls.Titanium-based zirconia composite were fabricated by SLM.The optical microscope(OM),scanning Electron microscopy(SEM),X-ray diffraction(XRD)and other methods have been used to research the phase composition and microstructure characteristics of titanium-based zirconia composite,and analysis its mechanical properties.The effects of process parameters and zirconia content on the microstructure and properties of SLM fabricated Titanium-based zirconia composites were researched.The effects of selected laser melting process parameters(laser power,P;scanning speed,V;hatch distance,H)on the relative density and fabricating quality of titanium-based oxide materials were researched.As the zirconia mass fraction increases,the process window for SLM fabricating titanium-based zirconia composites becomes narrower.Under the process parameters of P=450W,V=2500mm/s,H=70?m,the relatively density of TC4 is 97.63%;Under the process parameters of P=370W,V=1100mm/s and H=100?m,the highest relatively density of TC4-3nYSZ composite material was obtained,reaching 97.56%;Under the process parameters of P=370W,V=1200mm/s and H=80?m,the highest relatively density of TC4-3nYSZ composite material was obtained,reaching 96.95%.The influence of zirconia content on the microstructure of titanium matrix was researched.SLM fabricated TC4 titanium alloy is mainly composed of primary a phase,martensitic ? 'phase and a small amount of ? phase.SLM fabricated TC4-3nYSZ composite is mainly composed of martensitic a' phase and a small amount of ? phase;SLM fabricated TC4-10nYSZ composite material is mainly composed of martensitic ?' phase,a small amount of ? phase,and a small amount of zirconia particles.added After zirconia,compared to TC4 titanium alloy,the TC4-3nYSZ composite titanium matrix ? phase matrix grains are finer,the martensite?' phase becomes more slender,and the TC4-10nYSZ composite beta phase matrix grains are refined.The martensite ?' phase aspect ratio decreases and becomes shorter and thicker.The processing parameter that has the greatest effect on the microstructure of Titanium-based zirconia composite fabricated by SLM is the hatch distance,followed by the scanning speed,and finally the laser power;as the hatch distance increases,the lane width increases and the martensite ?' phase aspect ratio increase.As the scanning speed increases,the lane width decreases and the martensitic ?' phase aspect ratio increases.As the laser power increases,the melt lane width and martensitic ?' phase aspect ratio increases slightly.The compressive strength of SLM-formed TC4 titanium alloy is 1708MPa;the average hardness is 381HV;the weight loss is 0.073g(100N,30min).Compared with SLM fabricated TC4 titanium alloy,the compression strength and hardness of the titanium based zirconia composites have been greatly improved.The compressive strength of SLM fabricated TC4-3nYSZ and TC4-10nYSZ composite materials reached 1982MPa and 2153MPa;the average hardness reached 440 HV and 511 HV;TC4-3nYSZ composite material grinding loss is 0.042g,reduced by 41%;TC4-10nYSZ composite material grinding loss is 0.100g,increased by 39.3%. |
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