title: Microyielding of core-shell crystal dendrites in a bulk-metallic-glass matrix composite.
abstract: In-situ synchrotron x-ray experiments have been used to follow the evolution of the diffraction peaks for crystalline dendrites embedded in a bulk metallic glass matrix subjected to a compressive loading-unloading cycle. We observe irreversible diffraction-peak splitting even though the load does not go beyond half of the bulk yield strength. The chemical analysis coupled with the transmission electron microscopy mapping suggests that the observed peak splitting originates from the chemical heterogeneity between the core (major peak) and the stiffer shell (minor peak) of the dendrites. A molecular dynamics model has been developed to compare the hkl-dependent microyielding of the bulk metallic-glass matrix composite. The complementary diffraction measurements and the simulation results suggest that the interface, as Maxwell damper, between the amorphous matrix and the (211) crystalline planes relax under prolonged load that causes a delay in the reload curve which ultimately catches up with the original path.
authors.affiliation: Department of Chemical and Materials Engineering and Center for Neutron Beam Applications, National Central University, Jhongli, 32001, Taiwan (R.O.C.).
authors.forename: E-Wen
authors.initials: EW
authors.lastname: Huang
authors.affiliation: Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
authors.forename: Junwei
authors.initials: J
authors.lastname: Qiao
authors.affiliation: 1] Manchester X-ray Imaging Facility, School of Materials, University of Manchester, Manchester, M13 9PL, United Kingdom [2] National Physical Laboratory, Materials Division, London, M1 7HS, United Kingdom.
authors.forename: Bartlomiej
authors.initials: B
authors.lastname: Winiarski
authors.affiliation: National Center for High-Performance Computing, No. 22, Keyuan Rd., Central Taiwan Science Park, Taichung 40763, Taiwan (R.O.C.).
authors.forename: Wen-Jay
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: European Synchrotron Radiation Facility Beamline ID15A, Grenoble, France.
authors.forename: Mario
authors.initials: M
authors.lastname: Scheel
authors.affiliation: Department of Materials Science and Engineering, University of Tennessee, Knoxville TN 37996-2200, USA.
authors.forename: Chih-Pin
authors.initials: CP
authors.lastname: Chuang
authors.affiliation: Department of Materials Science and Engineering, University of Tennessee, Knoxville TN 37996-2200, USA.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Liaw
authors.affiliation: Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 24-107Cambridge, MA 02139.
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Lo
authors.affiliation: State Key Laboratory for Advanced Metals and Materials, University of Science and Technology, Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: European Synchrotron Radiation Facility Beamline ID15A, Grenoble, France.
authors.forename: Marco
authors.initials: M
authors.lastname: Di Michiel