title: Microstructure, elastic deformation behavior and mechanical properties of biomedical β-type titanium alloy thin-tube used for stents.
abstract: Cold-deformability and mechanical compatibility of the biomedical β-type titanium alloy are the foremost considerations for their application in stents, because the lower ductility restricts the cold-forming of thin-tube and unsatisfactory mechanical performance causes a failed tissue repair. In this paper, β-type titanium alloy (Ti-25Nb-3Zr-3Mo-2Sn, wt%) thin-tube fabricated by routine cold rolling is reported for the first time, and its elastic behavior and mechanical properties are discussed for the various microstructures. The as cold-rolled tube exhibits nonlinear elastic behavior with large recoverable strain of 2.3%. After annealing and aging, a nonlinear elasticity, considered as the intermediate stage between "double yielding" and normal linear elasticity, is attributable to a moderate precipitation of α phase. Quantitive relationships are established between volume fraction of α phase (Vα) and elastic modulus, strength as well as maximal recoverable strain (εmax-R), where the εmax-R of above 2.0% corresponds to the Vα range of 3-10%. It is considered that the "mechanical" stabilization of the (α+β) microstructure is a possible elastic mechanism for explaining the nonlinear elastic behavior.
authors.affiliation: Northwest Institute for Non-ferrous Metal Research (NIN), 96 Weiyang Road, Xi'an 710016, China; Department of Materials Science and Engineering, Engineering Faculty, National University of Singapore, 117575 Singapore, Singapore. Electronic address: msety@nus.edu.sg.
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Northwest Institute for Non-ferrous Metal Research (NIN), 96 Weiyang Road, Xi'an 710016, China.
authors.forename: Zhentao
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Department of Materials Science and Engineering, Engineering Faculty, National University of Singapore, 117575 Singapore, Singapore.
authors.forename: Chun Yee Aaron
authors.initials: CY
authors.lastname: Ong
authors.affiliation: Defence Materials Technology Centre, School of Mechanical and Mining Engineering, The University of Queensland, Brisbane 4072, QLD, Australia.
authors.forename: Damon
authors.initials: D
authors.lastname: Kent
authors.affiliation: Defence Materials Technology Centre, School of Mechanical and Mining Engineering, The University of Queensland, Brisbane 4072, QLD, Australia.
authors.forename: Gui
authors.initials: G
authors.lastname: Wang
mesh_terms: D000497:Alloys; D055119:Elastic Modulus; D008422:Materials Testing; D055595:Mechanical Phenomena; D044367:Phase Transition; D015607:Stents; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; C023988:beta titanium; D014025:Titanium
keywords: Elastic deformation behavior; Phase precipitation; Thin-tube; α″ Martensite; β-Type titanium alloy