Modelling Semi-Solid Behaviour and Brittle Temperature Range

2019 ◽  
Vol 285 ◽  
pp. 361-366 ◽  
Author(s):  
Khalil Traidi ◽  
Véronique Favier ◽  
Philippe Lestriez ◽  
Karl Debray ◽  
Laurent Langlois ◽  
...  
Keyword(s):  
Solid State ◽  
Material Properties ◽  
Solid Phase ◽  
Thermal Conditions ◽  
Tensile Tests ◽  
Internal Variable ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Semi Solid ◽  
First Time

In this paper, a new elastic viscoplastic micromechanical modelling is proposed to represent the semi-solid behaviour and predict the ductile-brittle transition of the C38LTT near the solidus. It is based on a viscoplastic modelling previously presented in [1]. The originality of the new model comes from three main enhancements: the transition between the solid state and the semi-solid state was included meaning that the material properties were taken temperature-dependent, the elastic properties was taken into account similarly as [2] and the evolution of the internal variable describing the degree of agglomeration of the solid phase was enhanced. The model was implemented in the commercial software FORGE©. Tensile tests representing the experimental thermal conditions and obtained using a GLEEBLE© machine were simulated. The comparison of the predicted and experimental results shows that, for the first time to our knowledge, the three steps of the load-displacement response and ductile-brittle transition were successfully described.

scholarly journals Review of Thermophysical Property Data of Octadecane for Phase-Change Studies

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2974 ◽  
Author(s):  
Moritz Faden ◽  
Stephan Höhlein ◽  
Joschka Wanner ◽  
Andreas König-Haagen ◽  
Dieter Brüggemann
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Confidence Interval ◽  
Phase Change ◽  
Thermophysical Property ◽  
Confidence Intervals ◽  
Material Properties ◽  
Solid Phase ◽  
Temperature Dependent ◽  
Property Data

In this work we derive temperature-dependent functions for the most important material properties needed for phase change studies with octadecane. Over 80 references are reviewed in which at least one thermophysical property of octadecane is measured. The functions are valid ±40 K around the melting temperature and are surrounded by their confidence interval. It turns out that the values for the solid phase have much broader confidence intervals than the ones of the liquid phase. Hence, more accurate measurements are particularly desirable for the solid state material properties.

Werkstückerwärmung für das Thixoforming*/Heating workpieces for Thixoforming - Using inductor as sensor for monitoring the heating process of semi-solid material

2017 ◽  
Vol 107 (05) ◽  
pp. 340-345
Author(s):  
J. Uphoff ◽  
A. Lechler ◽  
A. Prof. Verl
Keyword(s):  
Solid State ◽  
Solid Fraction ◽  
Material Properties ◽  
Solid Material ◽  
Heating Process ◽  
Inductive Heating ◽  
Inductor Coil ◽  
Specific Material ◽  
Semi Solid

Das Thixoforming nutzt bei der Formgebung besondere Materialeigenschaften zur Herstellung metallischer Bauteile. Die verwendeten Legierungen müssen dazu in den sogenannten teilflüssigen Bereich erwärmt werden. Das Einstellen des geforderten Fest-Flüssig-Verhältnisses stellt besondere Anforderungen an die Erwärmung. Betrachtet werden verschiedene Messverfahren, welche die Induktorspule bei der induktiven Erwärmung als Sensor nutzen.   Thixoforming uses specific material properties for shaping metal workpieces. For this purpose, the alloys need to be heated to the so-called semi-solid state. The adjustment of the desired semi-solid fraction imposes high requirements on the heating process. Various measurement principles, which use the inductor-coil as a sensor in inductive heating processes, are presented.

Determination of Material Properties in the Semi-Solid State Using Gleeble Simulator

2007 ◽  
Author(s):  
Krzysztof Sołek ◽  
Roman Kuziak ◽  
Plato Kapranos
Keyword(s):  
Solid State ◽  
Material Properties ◽  
Semi Solid

scholarly journals Effect of the Parameters of Semi-Solid Processing on the Elimination of Sharp-Edged Primary Chromium Carbides from Tool Steel

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 713 ◽  
Author(s):  
Hana Jirková ◽  
Kateřina Rubešová ◽  
Pavel Konopík ◽  
Kateřina Opatová
Keyword(s):  
Solid State ◽  
Tool Steel ◽  
Tensile Tests ◽  
Hydraulic Press ◽  
Chromium Carbides ◽  
Routine Basis ◽  
Forming Temperature ◽  
Electron Microscopes ◽  
Semi Solid ◽  
Scanning Electron Microscopes

Although conventional tool steels have been heat treated on a routine basis for decades, the search continues for new ways to eliminate their troublesome sharp-edged primary chromium carbides, which impair toughness. One of the available techniques is semi-solid processing, which involves partial melting of the workpiece. The structure after semi-solid processing consisted of a austenite and carbide-austenite network. The network can be broken up and its fragments distributed uniformly by subsequent forming with appropriate parameters. In this experimental study, X210Cr12 tool steel was heated to a semi-solid state, and after cooling to a solid state, worked in a hydraulic press. Suitable soaking temperatures were sought within an interval between 1200 °C and 1280 °C. The workpieces were quenched from the forming temperature in water or oil. In order to improve formability and reduce hardness, tempering was tested as well. Additional experimental regimes included conventional quenching and tempering. Once the appropriate parameters were chosen, the elimination of primary chromium carbides was successful. The resultant microstructures were fine and consisted of M-A constituent with a size of approximately 1 μm, and very fine Fe3C and Cr7C3 carbides. The hardness was in excess of 800 HV10. They were examined using optical and scanning electron microscopes. The carbides were characterized on transparent foils in a transmission electron microscope. Mechanical characteristics were determined in micro-tensile tests.

scholarly journals Using of Corn Gluten Growing of Trichoderma harzianum and production of acid protease

2008 ◽  
Vol 2 (1) ◽  
pp. 5-16
Author(s):  
زهرة محمود الخفاجي ◽  
لينا جاسم محمد ◽  
بتول زينل علي
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Trichoderma Harzianum ◽  
Solid Phase ◽  
Acid Protease ◽  
Protease Enzyme ◽  
Corn Gluten ◽  
First Time

The study was conducted to evaluate the utilization of corn cluten which is one of the agricultural wast products "especially the insoluble solid phase" for the first time as a culturing medium for Trichoderma harzianum and production of acid protease enzyme by solid state fermentation.

Temperature-Dependent Solid-state Luminescence and Reversible Phase Transition of (n-Bu4N)[Au(SC6H3-3,5-Me2)2]

2003 ◽  
Vol 32 (11) ◽  
pp. 1002-1003 ◽  
Author(s):  
Seiji Watase ◽  
Takayuki Kitamura ◽  
Nobuko Kanehisa ◽  
Masami Nakamoto ◽  
Yasushi Kai ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solid State ◽  
Temperature Dependent ◽  
Reversible Phase Transition ◽  
Reversible Phase ◽  
State Luminescence

scholarly journals Solid-Phase “Self-Hydrolysis” of [Zn(NH3)4MoO4@2H2O] Involving Enclathrated Water—An Easy Route to a Layered Basic Ammonium Zinc Molybdate Coordination Polymer

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4022
Author(s):  
Kende Attila Béres ◽  
István E. Sajó ◽  
György Lendvay ◽  
László Trif ◽  
Vladimir M. Petruševski ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Solid Phase ◽  
Water Molecules ◽  
Temperature Dependent ◽  
Dynamic Interactions ◽  
Ammonia Release ◽  
Successive Substitution ◽  
Red Dye ◽  
Hydrolysis Of ◽  
Zinc Molybdate

An aerial humidity-induced solid-phase hydrolytic transformation of the [Zn(NH3)4]MoO4@2H2O (compound 1@2H2O) with the formation of [(NH4)xH(1−x)Zn(OH)(MoO4)]n (x = 0.92–0.94) coordination polymer (formally NH4Zn(OH)MoO4, compound 2) is described. Based on the isostructural relationship, the powder XRD indicates that the crystal lattice of compound 1@2H2O contains a hydrogen-bonded network of tetraamminezinc (2+) and molybdate (2−) ions, and there are cavities (O4N4(μ-H12) cube) occupied by the two water molecules, which stabilize the crystal structure. Several observations indicate that the water molecules have no fixed positions in the lattice voids; instead, the cavity provides a neighborhood similar to those in clathrates. The @ symbol in the notation is intended to emphasize that the H2O in this compound is enclathrated rather than being water of crystallization. Yet, signs of temperature-dependent dynamic interactions with the wall of the cages can be detected, and 1@2H2O easily releases its water content even on standing and yields compound 2. Surprisingly, hydrolysis products of 1 were observed even in the absence of aerial humidity, which suggests a unique solid-phase quasi-intramolecular hydrolysis. A mechanism involving successive substitution of the ammonia ligands by water molecules and ammonia release is proposed. An ESR study of the Cu-doped compound 2 (2#dotCu) showed that this complex consists of two different Cu2+(Zn2+) environments in the polymeric structure. Thermal decomposition of compounds 1 and 2 results in ZnMoO4 with similar specific surface area and morphology. The ZnMoO4 samples prepared from compounds 1 and 2 and compound 2 in itself are active photocatalysts in the degradation of Congo Red dye. IR, Raman, and UV studies on compounds 1@2H2O and 2 are discussed in detail.

scholarly journals Temperature-Dependent Photoluminescence of ZnO Thin Films Grown on Off-Axis SiC Substrates by APMOCVD

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1035
Author(s):  
Ivan Shtepliuk ◽  
Volodymyr Khranovskyy ◽  
Arsenii Ievtushenko ◽  
Rositsa Yakimova
Keyword(s):  
Optical Properties ◽  
Structural Quality ◽  
Organic Chemical ◽  
Zno Films ◽  
Vicinal Surfaces ◽  
Temperature Dependent ◽  
Step Flow ◽  
Step Flow Growth ◽  
First Time ◽  
Temperature Dependent Photoluminescence

The growth of high-quality ZnO layers with optical properties congruent to those of bulk ZnO is still a great challenge. Here, for the first time, we systematically study the morphology and optical properties of ZnO layers grown on SiC substrates with off-cut angles ranging from 0° to 8° by using the atmospheric pressure meta–organic chemical vapor deposition (APMOCVD) technique. Morphology analysis revealed that the formation of the ZnO films on vicinal surfaces with small off-axis angles (1.4°–3.5°) follows the mixed growth mode: from one side, ZnO nucleation still occurs on wide (0001) terraces, but from another side, step-flow growth becomes more apparent with the off-cut angle increasing. We show for the first time that the off-cut angle of 8° provides conditions for step-flow growth of ZnO, resulting in highly improved growth morphology, respectively structural quality. Temperature-dependent photoluminescence (PL) measurements showed a strong dependence of the excitonic emission on the off-cut angle. The dependences of peak parameters for bound exciton and free exciton emissions on temperature were analyzed. The present results provide a correlation between the structural and optical properties of ZnO on vicinal surfaces and can be utilized for controllable ZnO heteroepitaxy on SiC toward device-quality ZnO epitaxial layers with potential applications in nano-optoelectronics.

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