scholarly journals Determination of Quantity and Localization of Liquid in the Semi-Solid State Using both 3D X-Ray Microtomography and 2D Techniques for Steel Thixoforming

2012 ◽  
Vol 192-193 ◽  
pp. 191-196
Author(s):  
Guo Chao Gu ◽  
Raphaël Pesci ◽  
Eric Becker ◽  
Laurent Langlois ◽  
Régis Bigot
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Solid State ◽  
Room Temperature ◽  
Great Influence ◽  
Ex Situ ◽  
X Ray ◽  
Semi Solid

The distribution of liquid at the semi solid state is one of the most important parameters for steel thixoforging. It has a great influence on the viscosity of the material, on the flows and finally on the final shape and mechanical properties of the thixoforged parts. Both ex situ and in situ 3D X-ray microtomography characterizations have been carried out to determine the quantity and localization of liquid at high temperature of M2 steel slugs. Microtomography was first performed ex situ at room temperature on samples heated and quenched from semi-solid state. The specimens were also scanned in situ directly at high temperature. The obtained results have been compared to 2D observations using EDS technique in SEM on heated and quenched specimens. They showed a good correlation making both approaches very efficient for the study of the liquid zones at the semi-solid state

Research on Thixoforging Magazine Plate of AZ91D Magnesium Alloy in Semi-Solid State

2006 ◽  
Vol 116-117 ◽  
pp. 267-270 ◽  
Author(s):  
Ju Fu Jiang ◽  
Shou Jing Luo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Solid State ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Great Influence ◽  
Technological Parameters ◽  
Az91d Magnesium Alloy ◽  
Preheating Temperature ◽  
Semi Solid

The thixoforging process in which magazine plates of AZ91D magnesium alloy were thixoforged in semi-solid state using semi-solid billets prepared by common SIMA method and new SIMA method was investigated. The results show that the pressure has a great influence on the semi-solid billet’s ability to fill die’s cavity. When the pressure is 500KN, the semi-solid billet can’t fill the die’s cavity completely. When the pressure is 2000KN, the semi-solid billet can fill the die’s cavity completely. Room temperature mechanical properties, such as yield strength of 201.4MPa, ultimate tensile strength of 321.8MPa and elongation of 15.3%, can be obtained successfully when the technological parameters, including pressure of 200KN, die preheating temperature of 723K, holding for 20min at 818K, are satisfied. Comparing with common SIMA, mechanical properties of room temperature and high temperature at 373Kare enhanced heavily.

Phase relations in the Ba–Sr–Co–Fe–O system at 1273 K in air

2009 ◽  
Vol 42 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Zhèn Yáng ◽  
Ashley S. Harvey ◽  
Anna Infortuna ◽  
Ludwig J. Gauckler
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Solid State Reaction Method ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray

Selected compositions of the Ba–Sr–Co–Fe–O system were synthesized from powders by the solid-state reaction method. Samples were equilibrated at 1273 K for 36 000 s in air. The resulting powders were characterized by X-ray diffraction (XRD) at room temperature and by high-temperaturein situXRD. The phases present in the BaxSr1−xCoyFe1−yO3−δsystem are outlined for 1273 K in air. For most of the quaternary compositions, the cubic perovskite is formed, except for the compositions withx= 1 (excludingy= 0.4),y= 1 andx,y= 0.8, where the phases mainly show hexagonal distortions, andx, y= 0, for which a predominant cubic phase is mixed with other phases.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

scholarly journals High Temperature Texture Goniometer for in Situ Measurements of Transformation Textures

1998 ◽  
Vol 30 (3-4) ◽  
pp. 125-132
Author(s):  
G. Brückner ◽  
F. R. Reher ◽  
G. Gottstein
Keyword(s):  
High Temperature ◽  
Texture Evolution ◽  
Sample Surface ◽  
Texture Measurement ◽  
X Ray ◽  
Reducing Gas ◽  
Gas Atmosphere ◽  
Computer Controlled

A high temperature stage was designed for mounting onto a computer controlled four circle X-ray texture goniometer. This technique allowed to conduct in situ texture measurement, i.e. the determination of the texture evolution during rather than subsequent to annealing. The device was employed for temperatures up to 1000°C.The furnace consisted of a resistance wire of Pt30Rh, which was isolated against the specimen with Al2O3 glue. The furnace with the specimen was covered by a hemispherical KaptonTM foil. Inside the hemisphere a reducing gas atmosphere was used to avoid oxidation of the sample surface.

Grazing Incidence X-Ray Scattering Studies of the Structure and Morphology of the Ni/Mgo(001), Co/Nio(111) and Nife/Nio(111) Interfaces During their in Situ Growth

1999 ◽  
Vol 562 ◽  
Author(s):  
G. Renaud ◽  
A. Barbier ◽  
C. Mocuta
Keyword(s):  
High Temperature ◽  
Magnetic Measurements ◽  
Grazing Incidence ◽  
Ex Situ ◽  
Crystallographic Structure ◽  
Temperature Oxidation ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

ABSTRACTCombined in situ structural and ex situ magnetic studies of the Co/NiO(111) and Ni81Fe19/NiO(111) interfaces are presented. The Co and Permalloy films were grown on NiO(111) single crystals. Structural studies were performed by Grazing Incidence X-ray Scattering during growth. The effect of the temperature of the substrate during deposition was investigated. Under specific growth conditions, almost pure FCC Co and NiFe films can be obtained, with small quantities of twins. Magnetic measurements were performed ex situ by Magneto-Optical Kerr Effect (MOKE). A strong correlation between the magnetic properties and the crystallographic structure of the Co film is evidenced. High coercive fields are measured for all samples. High temperature annealing of the NiFe film leads to an improved crystalline quality, but the interface becomes reactive and diffuse: part of the Fe diffuses into the NiO substrate and forms an interface compound, likely to be the spinel NiFe2O4. We also report an in situ grazing incidence X-ray scattering study of the Ni/MgO(001) interface during its formation at room temperature. In-plane measurements reveal that the interface is sharp and that the epitaxial relationship is complex. Two distinct lattices are found to exist: expanded Ni(001) and Ni(110). The latter exhibits several orientations with respect to the substrate depending on the thickness. The Ni(110) orientations disappear by annealing at high temperature, leaving only the Ni cube/cube orientation. The layer was also almost fully transformed into NiO(001) by high temperature oxidation.

scholarly journals Application of X-Ray Microtomography to Quantify the Liquid Fraction of M2 Steel for Semi-Solid Forming Process

2013 ◽  
Vol 554-557 ◽  
pp. 547-552 ◽  
Author(s):  
Guo Chao Gu ◽  
Raphaël Pesci ◽  
Eric Becker ◽  
Laurent Langlois ◽  
Régis Bigot
Keyword(s):  
Mechanical Properties ◽  
Solid State ◽  
Liquid Fraction ◽  
High Energy ◽  
Material Behavior ◽  
Model Alloy ◽  
Processing Temperature ◽  
Volume Percentage ◽  
X Ray ◽  
Semi Solid

Thixoforging, one variant of semi-solid metal processing in which the metallic alloys are processed at low liquid fraction (0.1< Fl < 0.3), is used to produce complex parts with high mechanical properties. Steel thixoforging faces more challenges as compared to that of low melting point materials due to high processing temperature and lack of understanding of the thermomechanical behavior of materials in the given conditions. It is crucial to study the microstructure at the semi-solid state to improve the understanding of the thixoforging process since the material behavior strongly depends on main parameters: the liquid fraction, its distribution as well as the coherence of the solid skeleton. The microstructure has a great influence on the viscosity of the material, on the flows and finally on the final shape and mechanical properties of the thixoforged parts. Here, the characterization of the volume percentage and distribution of liquid fraction at the semi-solid state with high energy 3D X-ray microtomography was investigated on M2 steel grade as a ‘model’ alloy. The obtained results have been compared to 2D observations using EDS technique in SEM on heated and quenched specimens. They showed a good correlation making both approaches very efficient for the study of the liquid zones at the semi-solid state.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2019 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.51 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

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