title: Wear mechanism and tribological characteristics of porous NiTi shape memory alloy for bone scaffold.
abstract: 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.
authors: Department of Physics & Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China. shuilin.wu@gmail.com
authors: Shuilin
authors: S
authors: Wu
authors: Xiangmei
authors: X
authors: Liu
authors: Guosong
authors: G
authors: Wu
authors: Kelvin W K
authors: KW
authors: Yeung
authors: Dong
authors: D
authors: Zheng
authors: C Y
authors: CY
authors: Chung
authors: Z S
authors: ZS
authors: Xu
authors: Paul K
authors: PK
authors: Chu
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D001842:Bone and Bones / Q000601:surgery*; D019544:Equipment Failure Analysis; D006244:Hardness; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry*; D044367:Phase Transition; D016062:Porosity; D019736:Prostheses and Implants; D013314:Stress, Mechanical; D013499:Surface Properties; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: NiTi shape memory alloys; bone scaffold; phase transformation; porous; tribological behavior