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Showing papers in "Acta Materialia in 2002"


Journal ArticleDOI
TL;DR: In this paper, the effects of the substrate on the determination of mechanical properties of thin films by nanoindentation were examined, and the properties of aluminum and tungsten films on the following substrates: aluminum, glass, silicon and sapphire.

1,410 citations


Journal ArticleDOI
TL;DR: In this article, a new indicator of glass-forming ability (GFA) for bulk metallic glasses (BMGs) is proposed based on crystallization processes during cooling and reheating of the supercooled liquid.

1,121 citations


Journal ArticleDOI
TL;DR: A grain refinement mechanism induced by plastic deformation during the SMA treatment in Fe was proposed in this article, which involves formation of dense dislocation walls (DDWs) and dislocation tangles (DTs) in original grains and in the refined cells under further straining.

889 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated yield strength at ambient temperature and creep resistance between 225 and 300°C in dilute Al(Sc) alloys containing coherent Al3Sc precipitates, which were grown by heat-treatments to radii in the range 1.4-9.6 nm.

634 citations


Journal ArticleDOI
TL;DR: In this article, the microstructure of a nanocrystalline Mg97Zn1Y2 bulk alloy prepared by warm extrusion of rapidly solidified powders has been investigated by a combination of techniques, such as conventional high-resolution transmission electron microscopy (HRTEM), atomic-resolution high-angle annular dark field scanning-TEM (HAADF-STEM) with Z-contrast and energy-dispersive X-ray spectroscopy (EDS) with a sub-nanometer electron probe.

605 citations


Journal ArticleDOI
TL;DR: There are more than 200 different methods for measuring thin film adhesion, suggesting it to be material, geometry and even industry specific as discussed by the authors, suggesting that the major extrinsic variables are film stress, extent of delamination, thickness and temperature while the major intrinsic ones are modulus, yield strength, the thermodynamic work of adhesion and one or more length scales.

600 citations


Journal ArticleDOI
TL;DR: In this paper, the microstructure of a Ni-rich NiTi shape memory alloy and its influence on the thermal characteristics of martensitic transformations were studied. But the authors did not consider the effect of stress on the precipitation process of Ni4Ti3-precipitates.

585 citations


Journal ArticleDOI
Masayuki Shimada1, Hiroyuki Kokawa1, Zhi Wang1, Yutaka S. Sato1, Isao Karibe1 
TL;DR: In this paper, the effects of process parameters, pre-strain, annealing temperature, etc. on grain boundary character distribution and intergranular corrosion in thermomechanical treatment were examined during grain boundary engineering of type 304 austenitic stainless steel.

517 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that grain boundaries are in a metastable thermodynamic equilibrium in the presence of solute atoms and, therefore, grain coarsening is stopped as there is no driving force.

511 citations


Journal ArticleDOI
TL;DR: In this article, the microstructure of commercially available nanocrystalline (nc) electroplated Ni foils is studied by means of Xray diffraction and transmission electron microscopy.

501 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe the fabrication and characterization of composites with a shape memory polymer matrix and SiC nanoparticulate reinforcements, which are active materials capable of recovering relatively large mechanical strains due to the application of heat.

Journal ArticleDOI
TL;DR: In this paper, the stability and evolution of ferroelectric domain structures in thin films are studied and Elastic solutions are derived for both elastically anisotropic and isotropic thin films with arbitrary domain structures, subject to mixed stress-free and constraint boundary conditions.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the UFG microstructures in the surface layer of an aluminum alloy 7075 heavily worked by ultrasonic shot peening and found that the grain subdivision into the subgrains was the main mechanism responsible for grain refinement.

Journal ArticleDOI
TL;DR: Bulk metallic glasses with a maximum thickness (tmax) of 10-27 mm were synthesized in the Fe43Cr16Mo16(C, B, P)25 system over a wide composition range by copper mold casting as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, a massively parallel molecular-dynamics code for the simulation of polycrystal plasticity is used to elucidate the intricate interplay between dislocation and GB processes during room-temperature plastic deformation of model nanocrystalline-Al microstructures.

Journal ArticleDOI
TL;DR: In this article, two fine-grained 7075Al alloys with a grain size of 3.8 and 7.5 μm were subjected to friction stir processing (FSP) with different processing parameters.

Journal ArticleDOI
TL;DR: In this article, the kinetics and topology of grain growth in 3D are simulated using a phase-field model of an ideal polycrystal with uniform grain-boundary mobilities and energies.

Journal ArticleDOI
TL;DR: In this article, diffusion data in various constituent binary systems were assessed to establish a multicomponent diffusion mobility database, and the diffusion assessment relied on an existing thermodynamic database for the calculation of needed thermodynamic factors.

Journal ArticleDOI
TL;DR: In this paper, the grain-size scaling of the Coble creep is found to decrease from d−3 to d−2 when the grain diameter becomes of the order of the GB width.

Journal ArticleDOI
TL;DR: In this article, the deformation behavior of Mg-Zn-Y alloys at room and elevated temperatures has been investigated and the variation of the flow stress in the alloys is characterized by linking the microstructural evolution during deformation at high temperatures.

Journal ArticleDOI
TL;DR: In this paper, the cyclic deformation of single crystal NiTi containing Ti3Ni4 precipitates of various sizes has been investigated and it has been shown that the degradation resistance of NiTi is strongly dependent on crystallographic orientation under compression, orientations approaching the [100] pole of the stereographic triangle possess the highest fatigue resistance.

Journal ArticleDOI
TL;DR: In this paper, the microscopic mechanism leading to the stabilization of cubic and tetragonal forms of zirconia (ZrO2) is analyzed by means of a self-consistent tight-binding model.

Journal ArticleDOI
TL;DR: In this paper, the authors quantified the active strengthening mechanisms at room temperature and explicitly considered solid solution strengthening, grain boundary strengthening, and Al3(Sc,Zr) precipitate strengthening.

Journal ArticleDOI
TL;DR: In this article, the microstructural evolution during the process of cold-rolling and annealing of martensite starting structure can produce ultrafine grained structure in carbon steel.

Journal ArticleDOI
TL;DR: In this article, the authors used differential scanning calorimetry (DSC) for a systematic investigation of the evolution of transformation behavior with ageing temperature and time, and demonstrated that during ageing of Ni-rich NiTi alloys, DSC curves exhibit two transformation peaks on cooling after short ageing times, three after intermediate ageing times and finally again two peaks after long ageing times.

Journal ArticleDOI
TL;DR: Experiments were conducted to evaluate the grain refinement introduced by equal-channel angular pressing (ECAP) in three different Al-3% Mg alloys containing either 2% Sc, 2% Zr or a combination of 2%Sc and Zr as mentioned in this paper, but superplasticity was not achieved in the Al-Mg-Zr alloy due to the onset of rapid grain growth at 573 K.

Journal ArticleDOI
TL;DR: The tensile behavior of composites produced by infiltrating ceramic particle beds with high purity (99.99%) is studied as a function of reinforcement size and chemistry (Al2O3 and B4C) as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, the grain-size dependent thermal conductivity of nanocrystalline yttria-stabilized zirconia from 6-480k was investigated and the results suggest a new strategy for identifying improved thermal barrier materials by choosing materials with large interfacial thermal resistance and reduced dimensionality or grain size.

Journal ArticleDOI
TL;DR: In this paper, the structure, thermal stability and properties of a Cu-Cr-Zr alloy with 160 nm diameter produced by severe plastic deformation through equal-channel angular pressing (ECAP) are investigated.

Journal ArticleDOI
TL;DR: In this paper, the microstructural evolution does not saturate at large strains and the individual strength contributions are calculated and their addition leads to flow stress values and strain hardening behavior in good agreement with those determined experimentally.