Search

• The ambient temperature damping can be obtained in Ni-Fe-Ga strain glass alloys. • The maximum damping value is achieved in Ni-Fe-Ga alloys within the phase boundary. • The boundaries of martensitic nano-domains are very mobile in the phase boundary. [Display omitted] Strain glass alloys are promising candidates of high performance damping materials for their broad damping peaks. To realize the practical applications, the large damping capacity and broad ambient temperature range are highly desirable. However, the high damping behavior covering ambient temperature has not yet been achieved in strain glass systems, and how to obtain a maximum damping capacity in the same strain glass system remains unclear. Here, we reported the broad ambient temperature damping of Ni 73−x Fe x Ga 27 (x = 23.5–24.5) strain glass alloys. The damping capacity of Ni 73−x Fe x Ga 27 strain glass alloys increases as the compositions move towards the martensite/strain-glass phase boundary, and the maximum damping value (~0.12) is achieved in Ni 49.5 Fe 23.5 Ga 27 strain glass alloy within the phase boundary. The boundaries of martensitic nano-domain are very mobile in phase boundary region, which leads to broad and high damping peak around ambient temperature. Our results provide an effective way to design high performance damping materials. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical corrosion behavior of microarc oxidation (MAO) coatings produced at various oxidation times on AZ31 Mg alloys was studied in a simulated body fluid (SBF). The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to characterize the corrosion behavior. The influences of the MAO time on the microstructure and corrosion properties are discussed. The initial porosity of the MAO coating was evaluated by the potentiodynamic polarization method. Post-corrosion phase identification showed that hydroxyapatite (HA) was formed on the surface of the samples. The ratio of Ca/P in HA was determined by the X-ray Fluorescence (XRF) technique. A physical model of the corrosion process with equivalent circuits at different corrosion stages is proposed. [Copyright &y& Elsevier]