title: Effect of swaging on Young׳s modulus of β Ti-33.6Nb-4Sn alloy.
abstract: The effect of swaging on the Young's modulus of β Ti-33.6Nb-4Sn rods was investigated by X-ray diffraction, thermography, microstructural observations, deformation simulator analysis and cyclic tensile deformation. Stress-induced α″ martensite was stabilized by swaging, dependent on the diameter reduction rate during swaging. Thermography and deformation simulator analysis revealed that swaged rods were adiabatically heated, and consequently, stress-induced α″ underwent reverse transformation. Young's modulus, which was measured by the slope of the initial portion of the stress-strain curve, decreased from 56GPa in the hot-forged/quenched rod to 44GPa in the rapidly swaged rod with a high reduction rate and to 45GPa in the gradually swaged rod with a low reduction rate. The tangent modulus, which was measured by the slope of the tangent to any point on the stress-strain curve, decreased with strain even in the linear range of the stress-strain curve of the hot-forged/quenched rod and the rapidly swaged rod, while the tangent modulus remained unchanged for the gradually swaged rod. It was found that Young's moduli in swaged β Ti-33.6Nb-4Sn rods were affected by stabilized α″ martensite. Low Young's modulus of 45GPa and high strength over 800MPa were obtained when the reverse transformation by adiabatic heating was suppressed and the stress-induced α″ was sufficiently stabilized by gradual swaging to a 75% reduction in cross section area.
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan. Electronic address: hanada@imr.tohoku.ac.jp.
authors.forename: Shuji
authors.initials: S
authors.lastname: Hanada
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Masahashi
authors.affiliation: Korea Institute of Industrial Technology, Incheon 406-840, Republic of Korea.
authors.forename: Taek Kyun
authors.initials: TK
authors.lastname: Jung
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Miyake
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Yutaka S
authors.initials: YS
authors.lastname: Sato
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kokawa
mesh_terms: D000497:Alloys / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry; D055119:Elastic Modulus; D006358:Hot Temperature; D008422:Materials Testing; D009556:Niobium / Q000737:chemistry; D013314:Stress, Mechanical; D014001:Tin / Q000737:chemistry; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D003722:Dental Alloys; D009556:Niobium; C093824:Martensite; D014001:Tin; D014025:Titanium
keywords: Adiabatic heating; Beta titanium alloy; Strength; Stress-induced martensite; Swaging; Young's modulus