β-TCP强化锌镁基复合材料的微观组织与性能研究

Microstructure and Properties ofβ-TCP Reinforced Zn-Mg Matrix Composites

纯锌有良好的生物相容性和适中的降解速率,但力学性能不理想,限制了其生物医学应用。针对纯锌力学性能较差的问题,利用高能球磨和放电等离子烧结技术制备具有核壳结构的Zn-10Mg-xβ-TCP(x=0,1,3,5)复合材料,选用磷酸三钙(β-TCP)作为增强相,以改善纯锌的力学性能和腐蚀性能。对Zn-10Mg-xβ-TCP(x=0,1,3,5)复合材料的微观组织、力学性能和腐蚀性能进行研究。结果表明,所有试样致密度均在95%以上,其中Zn-10Mg-1β-TCP由于β-TCP少量加入产生了弥散强化和位错强化作用,微纳力学硬度明显高于其他试样,达到4.008 GPa;抗压强度和抗弯强度分别为397 MPa和92 MPa,延伸率为6.5%;电化学实验中,Zn-10Mg-1β-TCP的腐蚀电流与锌镁合金相差不大,明显高于其他试样;在长期的浸泡实验中,试样Zn-10Mg-1β-TCP的平均腐蚀速率(0.221 mm/a)最大,并符合植入材料的降解速率要求。

Pure zinc has good biocompatibility and moderate degradation rate,but its mechanical properties are not ideal,which limits its biomedical applications.In view of the poor mechanical properties of zinc and its alloys,high-energy ball milling and spark plasma sintering techniques were used to prepare the alloy with core-shell structure Zn-10Mg-xβ-TCP(x=0,1,3,5)composites,β-TCP was selected as the reinforcing phase to improve the mechanical and corrosion properties of pure zinc.The microstructure,mechanical properties,and corrosion properties of Zn-10Mg-xβ-TCP(x=0,1,3,5)composite materials were investigated.The results show that all samples are relatively dense at 95%or above.The micro/nano-mechanical hardness of Zn-10Mg-1β-TCP is significantly higher than that of other samples,reaching 4.008 GPa;compressive strength and bending strength are 397 MPa and 92 MPa,respectively,and elongation is 6.5%,This is due to the small addition ofβ-TCP which produces dispersion strengthening and dislocation strengthening.In the electrochemical experiment,the corrosion current of Zn-10Mg1β-TCP is not much different from that of zinc-magnesium alloy,which is significantly higher than that of other samples;in the long-term immersion experiment,the average corrosion current of sample Zn-10Mg-1β-TCP is the largest and meets the degradation rate requirements of implant material.