Papers by Author: N. Mattern

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Authors: W. Pitschke, N. Mattern, H.U. Hermann
103
Authors: N. Mattern, Matvei Zinkevich, H. Ehrenberg, M. Knapp, A. Handstein
402
Authors: N. Mattern, M. Müller, A. Teresiak, U. Kühn, H.D. Bauer, H. Wendrock
701
Authors: M. Hecker, N. Mattern, W. Brückner, C.M. Schneider
Abstract: The subject of the present investigation is the influence of annealing on the microstructure of Co thin films. In particular, the evolution of the texture during annealing is studied and compared with that of Co/Cu multilayers of different individual layer thicknesses. 400nm thick Co films show a h.c.p. structure with a weak preference of the <001> texture component and a broad distribution of grain orientations. Annealing at about 350°C results in a strong increase of the h.c.p. <001> component, nearly complete disappearance of the statistical distribution and grain growth of a minor f.c.c. fraction in the films. In-situ XRD measurements on single Co films during annealing confirm that the texture change is irreversible. Multilayer stacks of Co/Cu layers show various texture changes depending on the individual layer thickness (ranging between 100nm and 1nm). Generally, with decreasing individual layer thickness and increasing annealing temperature the f.c.c. content in the multilayers increases at the expense of the h.c.p. fraction.
193
Authors: M. Calin, J. Das, K.B. Kim, S. Pauly, N. Mattern, Jürgen Eckert
Abstract: The work hardening ability under room temperature compression of ductile Cu47.5Zr47.5Al5 and Cu47Ti33Zr11Ni8Si1 bulk metallic glass-forming alloys has been studied and compared. Both alloys exhibit high fracture strength, distinct work hardening and large plastic strain. Systematic investigations on the microstructural evolution reveal the occurrence of nano-scale heterogeneities, of both structural and chemical nature, which enables multiplication, branching, and restriction of the shear bands, thus controlling the plastic instability of metallic glasses. Phase separation in the liquid state leading to chemical inhomogeneities has been revealed for as-cast Cu47.5Zr47.5Al5 samples. In the case of Cu47Ti33Zr11Ni8Si1, a composite-type microstructure with in-situ formed nano-scale precipitates embedded in a glassy matrix is responsible for the distinct work hardening recorded on the stress-strain curves. The present results support the important role of nano-scale heterogeneities for promoting efficient work hardening in Cu-based metallic glass composites.
665
Authors: H.U. Hermann, W. Gruner, N. Mattern, H.D. Bauer, F. Fugaciu, Th. Schubert
193
Authors: N. Mattern, H.D. Bauer, Jürgen Eckert
185
Authors: U. Kühn, Jürgen Eckert, S. Scudino, A. Gebert, N. Radtke, N. Mattern, Ludwig Schultz
511
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