title: Nonhysteretic superelasticity of shape memory alloys at the nanoscale.
abstract: We perform molecular dynamics simulations to show that shape memory alloy nanoparticles below the critical size not only demonstrate superelasticity but also exhibit features such as absence of hysteresis, continuous nonlinear elastic distortion, and high blocking force. Atomic level investigations show that this nonhysteretic superelasticity results from a continuous transformation from the parent phase to martensite under external stress. This aspect of shape memory alloys is attributed to a surface effect; i.e., the surface locally retards the formation of martensite and then induces a critical-end-point-like behavior when the system is below the critical size. Our work potentially broadens the application of shape memory alloys to the nanoscale. It also suggests a method to achieve nonhysteretic superelasticity in conventional bulk shape memory alloys.
authors.affiliation: Multi-Disciplinary Materials Research Center, Frontier Institute of Science and Technology, and State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Ding
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Turab
authors.initials: T
authors.lastname: Lookman
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Otsuka
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Ren