放电等离子烧结制备生物Mg-Zn合金的组织及性能

Microstructures and Mechanical Properties of Biodegradable Magnesium-Zinc Alloy Fabricated by Spark Plasma Sintering

以Mg粉和Zn粉为原料,采用高能球磨混粉和放电等离子烧结(SPS)的方法制备了Zn含量为0%,2%,4%,6%,8%(质量分数)的生物Mg-Zn合金,对其显微组织、力学性能和腐蚀性能进行了研究。结果表明:制备的Mg-Zn合金内部结构致密,组织分布均匀;显微硬度(HV)和抗压强度随Zn含量的增加而增加,当Zn含量为6%时达到最大值(690和379.5 MPa);模拟体液中的电化学腐蚀电位随Zn含量的增加而升高,腐蚀电流密度则降低,在6%时分别达到最大值和最小值。浸泡试验中,Zn含量为6%合金表现出最好的耐腐蚀性能,随Zn含量的增加,腐蚀形式由严重的点蚀和颗粒剥落转变为轻微的点蚀和颗粒内均匀的晶内腐蚀。

Biological Mg-x%Zn（x=2, 4, 6, 8, mass fraction） alloys were fabricated from pure magnesium and zinc powders using high-energy ball milling and spark plasma sintering. The microstructure, mechanical properties and corrosion performance of the biological Mg-Zn alloys were investigated. The results show that the sintered samples have a compact and homogenous internal structure. The hardness（HV） and compression strength of the alloys increase with increasing Zn content, which reach their maximum（690 and 379.5 MPa, respectively） when Zn content is 6%. The corrosion potential increases with increasing Zn content, while the current density declines, which achieve their maximum and minimum, respectively when Zn content is 6%. Mg-6%Zn alloy shows the optimal corrosion resistance. Moreover, the corrosion mode in SBF transforms from severe crevice corrosion and pitting corrosion into internal corrosion of particles and slight pitting corrosion with the Zn content increasing.