Department of Physics & Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China.
J Biomed Mater Res A. 2013 Sep;101(9):2586-601. doi: 10.1002/jbm.a.34568. Epub 2013 Feb 11.
The abraded debris might cause osteocytic osteolysis on the interface between implants and bone tissues, thus inducing the subsequent mobilization of implants gradually and finally resulting in the failure of bone implants, which imposes restrictions on the applications of porous NiTi shape memory alloys (SMAs) scaffolds for bone tissue engineering. In this work, the effects of the annealing temperature, applied load, and porosity on the tribological behavior and wear resistance of three-dimensional porous NiTi SMA are investigated systematically. The porous structure and phase transformation during the exothermic process affect the tribological properties and wear mechanism significantly. In general, a larger porosity leads to better tribological resistance but sometimes, SMAs with small porosity possess better wear resistance than ones with higher porosity during the initial sliding stage. It can be ascribed to the better superelasticity of the former at the test temperature. The porous NiTi phase during the exothermic reaction also plays an important role in the wear resistance. Generally, porous NiTi has smaller friction coefficients under high loads due to stress-induced superelasticity. The wear mechanism is discussed based on plastic deformation and microcrack propagation.
磨屑可能会导致种植体与骨组织界面处的成骨细胞性骨溶解，从而导致种植体逐渐松动，最终导致骨植入物失效，这限制了多孔 NiTi 形状记忆合金（SMA）支架在骨组织工程中的应用。在这项工作中，系统研究了退火温度、外加负载和孔隙率对三维多孔 NiTi SMA 摩擦学行为和耐磨性的影响。放热过程中的多孔结构和相变对摩擦学性能和磨损机制有显著影响。一般来说，较大的孔隙率会导致更好的摩擦学阻力，但在初始滑动阶段，有时小孔隙率的 SMA 比高孔隙率的 SMA 具有更好的耐磨性，这归因于前者在测试温度下更好的超弹性。放热反应中的多孔 NiTi 相在耐磨性方面也起着重要作用。一般来说，由于应力诱导的超弹性，多孔 NiTi 在高载荷下具有较小的摩擦系数。根据塑性变形和微裂纹扩展讨论了磨损机制。
