title: New intrinsic mechanism on gum-like superelasticity of multifunctional alloys.
abstract: Ti-Nb-based Gum Metals exhibit extraordinary superelasticity with ultralow elastic modulus, superior strength and ductility, and a peculiar dislocation-free deformation behavior, most of which challenge existing theories of crystal strength. Additionally, this kind of alloys actually displays even more anomalous mechanical properties, such as the non-linear superelastic behavior, accompanied by a pronounced tension-to-compression asymmetry, and large ductility with a low Poisson's ratio. Two main contradictory arguments exist concerning the deformation mechanisms of those alloys, i.e., formation of reversible nanodisturbance and reversible martensitic transformation. Herein we used the in-situ synchrotron high-energy X-ray scattering technique to reveal the novel intrinsic physical origin of all anomalous mechanical properties of the Ti-24Nb-4Zr-8Sn-0.10O alloy, a typical gum-like metal. Our experiments provide direct evidence on two different kinds of interesting, stress-induced, reversible nanoscale martensitic transitions, i.e., the austenitic regions with B2 structure transform to α″ martensite and those with BCC structure transform to δ martensite.
authors.affiliation: State Key Laboratory for Advanced Metals and Materials, University of Science and Technology, Beijing 100083, P. R. China.
authors.forename: Jia-Peng
authors.initials: JP
authors.lastname: Liu
authors.forename: Yan-Dong
authors.initials: YD
authors.lastname: Wang
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Hao
authors.forename: Yunzhi
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhi-Hua
authors.initials: ZH
authors.lastname: Nie
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Ren
authors.forename: Zhao-Ping
authors.initials: ZP
authors.lastname: Lu
authors.forename: Jinguo
authors.initials: J
authors.lastname: Wang
authors.forename: Haoliang
authors.initials: H
authors.lastname: Wang
authors.forename: Xidong
authors.initials: X
authors.lastname: Hui
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.forename: Moon J
authors.initials: MJ
authors.lastname: Kim
authors.forename: Rui
authors.initials: R
authors.lastname: Yang