TY - JOUR A1 - Sturm, D. A1 - Heilmaier, M. A1 - Schneibel, J.H. A1 - Jéhanno, P. A1 - Skrotzki, Birgit A1 - Saage, H. T1 - The influence of silicon on the strength and fracture toughness of molybdenum N2 - Mo–Si alloys containing up to 1 wt.% Si were fabricated by powder-metallurgical processing and their lattice parameters, elastic constants, densities, grain sizes, strengths, ductilities, and fracture toughness values were measured. The yield strength was insensitive to the grain size, i.e., a Hall–Petch relationship was not observed. Generally, Si additions caused pronounced solid solution strengthening. However, for small Si concentrations (≤0.1 wt.%) solid solution softening was observed at room temperature and below. With increasing Si concentration, the room temperature ductility and fracture toughness dropped precipitously. This is attributed to the increase in strength and a transition from transgranular to intergranular fracture. KW - Molybdenum KW - Solid solution strengthening KW - Solid solution softening KW - Hall-Petch relationship PY - 2007 SN - 0921-5093 SN - 1873-4936 VL - 463 IS - 1-2 SP - 107 EP - 114 PB - Elsevier CY - Amsterdam AN - OPUS4-14820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Bachelier, G. A1 - Wiggins, S. M. A1 - Siegel, J. A1 - Solis, J. A1 - Krüger, Jörg A1 - Sturm, Heinz T1 - Femtosecond laser ablation of indium phosphide in air: dynamical, structural and morphological evolution N2 - The irradiation of single-crystalline indium phosphide (c-InP) by Ti:sapphire femtosecond laser pulses (130 fs, 800 nm) in air is studied by means of in-situ time resolved reflectivity measurements [fs-time-resolved microscopy (100 fs-10 ns) and point probing analysis (ns - µs)] and by complementary ex-situ surface analytical methods (Micro Raman Spectroscopy, Scanning Force, and Optical Microscopy). The dynamics of melting, ablation, and optical breakdown as well as structural changes resulting from rapid solidification are investigated in detail. Different laser-induced surface morphologies are characterized and discussed on the basis of recent ablation and optical breakdown models. KW - Femtosecond laser ablation KW - Optical breakdown KW - Time-resolved measurements KW - Semiconductor KW - Indium phosphide PY - 2010 SN - 1454-4164 VL - 12 IS - 3 SP - 421 EP - 426 PB - INOE & INFM CY - Bucharest AN - OPUS4-21082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heyde, M. A1 - Sturm, Heinz A1 - Geuss, Markus A1 - Ritter, C. A1 - Rademann, K. T1 - Rastersondenmikroskopie als Werkzeug der Lithographie für Nanostrukturen PY - 1999 SN - 0946-641X VL - 6 IS - 3 SP - 28 EP - 33 PB - Universität CY - Berlin AN - OPUS4-6861 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heyde, M. A1 - Sturm, Heinz T1 - A new application of scanning probe microscopy piezos T2 - Raster-Sonden-Mikroskopien und organische Materialien VII CY - Berlin, Germany DA - 1998-10-07 PY - 1998 AN - OPUS4-6466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sturm, Heinz A1 - Cappella, Brunero A1 - Heyde, M. A1 - Ritter, C. A1 - Rademann, K. T1 - Dislocation of antimony clusters on graphite by means of dynamic plowing nanolithography N2 - Antimony clusters of different shapes and dimensions have been obtained by evaporating antimony on graphite. The dependence of the shape and dimensions of the particles on the evaporation parameters (effective layer thickness, temperature, pressure) is discussed. A characterisation of the different structures is presented. In particular, the decoration of graphite steps is discussed. Clusters have been dislocated by means of dynamic plowing nanolithography, both in vector and in image pattern mode. The dependence of the energy needed to dislocate a cluster on its dimensions and position is discussed. KW - Antimony clusters KW - Nanolithography PY - 2001 DO - https://doi.org/10.1016/S0039-6028(00)01113-4 SN - 0039-6028 VL - 476 IS - 1-2 SP - 54 EP - 62 PB - Elsevier CY - Amsterdam AN - OPUS4-875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sturm, Heinz A1 - Heyde, M. A1 - Rademann, K. T1 - Measuring SPM Piezo Displacement Responses PY - 1999 SN - 1551-9295 VL - 99 IS - 4 SP - 24 EP - 26 PB - Microscopy Society of America CY - Wappingers Falls, NY AN - OPUS4-6860 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bovtun, V. A1 - Sturm, Heinz A1 - Leshchenko, M. A. A1 - Yakimenko, Y. T1 - Dynamics of nanodomains (clusters) and dielectric relaxation in disordered ferroelectrics KW - Lead magnoniobate KW - Phase-transition KW - Dispersion PY - 1997 SN - 0015-0193 SN - 1563-5112 VL - 190 IS - 1-4 SP - 161 EP - 166 PB - Taylor & Francis CY - New York, NY AN - OPUS4-6853 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Weiß, André A1 - Sturm, Heinz A1 - Kleemeier, M. A1 - Hartwig, A. A1 - Vogt, C. A1 - Fischer, R.X. T1 - Layered silicate epoxy nanocomposites: formation of the inorganic-carbonaceous fire protection layer N2 - The layered silicate (LS) modification and processing parameters applied control the morphology of the LS/polymer composites. Here, increasing the surface area of the LS particles by using alternative drying processes increases dispersion towards a more typical nanocomposite morphology, which is a basic requirement for promising flame retardancy. Nevertheless, the morphology at room temperature does not act itself with respect to flame retardancy, but serves as a prerequisite for the formation of an efficient surface protection layer during pyrolysis. The formation of this residue layer was addressed experimentally for the actual pyrolysis region of a burning nanocomposite and thus our results are valid without any assumptions or compromises on the time period, dimension, surrounding atmosphere or temperature. The formation of the inorganic-carbonaceous residue is influenced by bubbling, migration, reorientation, agglomeration, ablation, and perhaps also delamination induced thermally and by decomposition, whereas true sintering of the inorganic particles was ruled out as an important mechanism. Multiple, quite different mechanisms are relevant during the formation of the residue, and the importance of each mechanism probably differs from one nanocomposite system to another. The main fire protection effect of the surface layer in polymer nanocomposites based on non-charring or nearly non-charring polymers is the increase in surface temperature, resulting in a substantial increase in reradiated heat flux (heat shielding). KW - Nanocomposite KW - Fire retardancy KW - Epoxy resin KW - Fire behavior KW - Flammability PY - 2011 DO - https://doi.org/10.1002/pat.1644 SN - 1042-7147 SN - 1099-1581 VL - 22 IS - 12 SP - 1581 EP - 1592 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-24916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heyde, M. A1 - Sturm, Heinz T1 - SPM Techniques to characterise Electrical Properties of Nanometer sized Particles T2 - Raster-Sonden-Mikroskopien und organische Materialien VII CY - Berlin, Germany DA - 1998-10-07 PY - 1998 AN - OPUS4-6455 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero A1 - Geuss, Markus A1 - Sturm, Heinz A1 - Heyde, M. A1 - Rademann, K. A1 - Spangenberg, T. A1 - Niehus, H. T1 - Dynamic plowing nanolithography on polymethylmethacrylate using an atomic force microscope N2 - We present dynamic plowing nanolithography on polymethylmethacrylate films, performed with a scan-linearized atomic force microscope able to scan up to 250 μm with high resolution. Modifications of the surface are obtained by plastically indenting the film surface with a vibrating tip. By changing the oscillation amplitude of the cantilever, i.e., the indentation depth, surfaces can be either imaged or modified. A program devoted to the control of the scanning process is also presented. The software basically converts the gray scale of pixel images into voltages used to control the dither piezo driving cantilever oscillations. The advantages of our experimental setup and the dependence of lithography efficiency on scanning parameters are discussed. Some insights into the process of surface modifications are presented. KW - Nanolithography PY - 2001 UR - http://rsi.aip.org/ DO - https://doi.org/10.1063/1.1326053 SN - 0034-6748 SN - 1089-7623 VL - 72 SP - 136 EP - 141 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Arlt, C. A1 - Exner, W. A1 - Riedel, U. A1 - Sturm, Heinz A1 - Sinapius, M. ED - Wiedemann, M. ED - Sinapius, M. T1 - Nanoscaled boehmites' modes of action in a polymer and its carbon fiber reinforced plastic N2 - Laminates of carbon fiber reinforced plastic (CFRP), which are manufactured by injection technology, are reinforced with boehmite particles. This doping strengthens the laminates, whose original properties are weaker than those of prepregs. Besides the shear strength, compression strength and the damage tolerance, the mode of action of the nanoparticles in resin and in CFRP is also analyzed. It thereby reveals that the hydroxyl groups and even more a taurine modification of the boehmites' surface alter the elementary polymer morphology. Consequently a new flow and reaction comportment, lower glass transition temperatures and shrinkage, as well as a changed mechanical behavior occur. Due to a structural upgrading of the matrix (higher shear stiffness, reduced residual stress), a better fiber-matrix adhesion, and differing crack paths, the boehmite nanoparticles move the degradation barrier of the material to higher loadings, thus resulting in considerably upgraded new CFRP. KW - Nano particles KW - Epoxy KW - Aerospace PY - 2012 SN - 978-3-642-29189-0 SN - 978-3-642-29190-6 DO - https://doi.org/10.1007/978-3-642-29190-6_4 SP - 49 EP - 58 PB - Springer CY - Berlin AN - OPUS4-26496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -