Farabi Ehsan, Sharp Julie A, Vahid Alireza, Fabijanic Daniel M, Barnett Matthew R, Gallo Santiago Corujeira
Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216, Australia.
Institute for Frontier Materials, Deakin University, Geelong, Victoria 3216, Australia.
Mater Sci Eng C Mater Biol Appl. 2021 Mar;122:111897. doi: 10.1016/j.msec.2021.111897. Epub 2021 Jan 23.
A series of Zn-Al-Li alloys with potential application in bioresorbable implants were cast, thermomechanically processed and tested. The formation of secondary phases, such as LiZn, LiZnAl and AlLi, contributed to both dynamic recrystallization and grain refinement of the matrix (η-phase) during the hot-extrusion process, leading to grain sizes as small as 1.75 μm for Zn-4Al-0.6Li alloy (wt%). This alloy exhibited an ultimate tensile strength (UTS) of 451 MPa, a total elongation of 46% and a corrosion rate of 60 μm/year in simulated body fluid. The grain refinement played a major role in increasing the strength, but it also weakened the basal texture and promoted non-basal slip and grain boundary sliding, thus contributing to the increased plastic deformation of the alloy. The corrosion rate was affected by a layer of zinc oxide and phosphate formed in the early stages of the immersion tests. The corrosion products protected the substrate and tended to reduce the corrosion rate over time. The developed Zn-4Al-0.6Li and Zn-6Al-0.4Li alloys which showed promising mechanical and corrosion properties appeared to be cytocompatible in the mouse fibroblast cell line and human umbilical mesenchymal stem cells making them promising candidates for bioresorbable stent and implant applications.
铸造、热机械加工并测试了一系列在生物可吸收植入物中具有潜在应用价值的锌铝锂合金。诸如LiZn、LiZnAl和AlLi等第二相的形成，在热挤压过程中有助于基体（η相）的动态再结晶和晶粒细化，使得Zn-4Al-0.6Li合金（重量百分比）的晶粒尺寸小至1.75μm。该合金在模拟体液中的极限抗拉强度（UTS）为451MPa，总伸长率为46%，腐蚀速率为60μm/年。晶粒细化在提高强度方面起主要作用，但也削弱了基面织构并促进了非基面滑移和晶界滑动，从而导致合金塑性变形增加。腐蚀速率受浸泡试验早期形成的一层氧化锌和磷酸盐的影响。腐蚀产物保护基体，并随着时间的推移倾向于降低腐蚀速率。所开发的Zn-4Al-0.6Li和Zn-6Al-0.4Li合金表现出良好的机械性能和腐蚀性能，在小鼠成纤维细胞系和人脐间充质干细胞中似乎具有细胞相容性，使其成为生物可吸收支架和植入物应用的有前途的候选材料。
