灭菌温度对超细晶Zn-0.3Mn合金力学和腐蚀性能的影响

Effect of sterilization temperatures on the mechanical and corrosion properties of ultrafine-grained Zn-0.3Mn alloy

通过大塑性变形(铸造-热挤压-多道次旋锻)制备了面向医用骨科植入应用领域的可降解超细晶(UFG)Zn-0.3Mn合金(Original),进而研究了其在低温灭菌(t 55)、蒸汽灭菌(t 120)和干热灭菌(t 180)温度状态下微观组织、力学性能、腐蚀性能的变化。研究发现:随着灭菌温度的提高,合金再结晶程度逐步加剧,主相晶粒尺寸和MnZn 13相颗粒尺寸均有所增加;力学性能方面,合金的纳米硬度和弹性模量会随着灭菌温度升高而逐渐提高;腐蚀性能方面,归因于晶界密度和MnZn 13相比例降低,减少了腐蚀起始点,合金腐蚀速率逐步下降。因而,灭菌温度会对可降解超细晶Zn-0.3Mn合金微观组织、力学性能和腐蚀性能产生足够大的影响,对于锌基植入器械的灭菌方法要尽量避免升温过程。

In this study,a biodegradable ultrafine-grained(UFG)Zn-0.3Mn alloy(Original)for medical orthopedic implant applications was prepared by severe plastic deformation(casting-hot extrusion-multipass rotary forging).The changes in the microstructure,mechanical properties,and corrosion properties of this alloy under the conditions of low-temperature sterilization(t 55),steam sterilization(t 120),and dry heat sterilization(t 180)were also investigated.Results show that the degree of alloy recrystallization gradually intensifies at the microstructure level as the sterilization temperature increases.At the same time,the grain size of the main phase and the particle size of the MnZn 13 phase enlarge.In terms of mechanical properties,the nano hardness and elastic modulus of the alloy will gradually increase with the increase of sterilization temperature.The corrosion performance is attributed to the decreases in grain boundary density and MnZn 13 phase ratio.These decreases reduce the corrosion initiation point and gradually lower the corrosion rate of the alloy.Accordingly,the sterilization temperature will sufficiently affect the microstructure,mechanical properties,and corrosion behavior of the biodegradable UFG Zn-0.3Mn alloy.Therefore,the heating process should be avoided in the sterilization method of Zn-based implant devices.