Single Step Heat Treatment Cycle for Development of Isotropic Fe-Cr-Co Magnets

2012 ◽  
Vol 510-511 ◽  
pp. 315-320 ◽  
Author(s):  
S. Akbar ◽  
Z. Ahmad ◽  
M.S. Awan ◽  
M.N. Sarwar ◽  
M. Farooque
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Spinodal Decomposition ◽  
Permanent Magnets ◽  
Treatment Cycle ◽  
Melting Furnace ◽  
Decomposition Temperature ◽  
Single Step ◽  
Heat Treatment Cycle ◽  
Step Heat Treatment

This study is focused on the development of isotropic Fe-Cr-Co based permanent magnets. Two compositions Fe-25Co-30Cr-3.5Mo-0.8Ti-0.8 and Fe-24 Co-32Cr-0.5Si-0.8V-0.8Ti were tried to optimize by adjusting heat treatment cycle. A modified single step heat treatment cycle was established which made processing easy and quick. Alloys were prepared in tri-arc melting furnace under inert atmosphere of Argon. Samples were solution treated at 1250 °C for 5 hours followed by water quenching. Then a spinodal decomposition heat treatment cycle in the temperature range 620 645 °C was applied in order to produce magnetism in this material. Samples were characterized for metallographic, chemical, structural and magnetic properties using Optical microscope, Scanning electron microscope equipped with Energy dispersive spectrometer, X-ray diffractometer and DC magnetometer. This study reveals that magnetic properties are sensitive to the spinodal decomposition temperature. Only + 5 °C change in temperature from optimum temperature can cause remarkable attenuation in magnetic properties. Magnetic properties of the alloys were achieved by controlling the spinodal decomposition temperature and subsequent cooling rate. The best magnetic properties in Mo and V containing alloys were obtained as 880 Oe (Hc), 7960 G (Br), 2.3 MGOe (BHmax) and 700 Oe (Hc), 7750 G (Br), 1.8 MGOe (BHmax), respectively.

Synthesis of Si3N4 Powder by Thermal Decomposition of SI(NH)2

1992 ◽  
Vol 287 ◽  
Author(s):  
Silvia Ampuero ◽  
Paul Bowen ◽  
Terry A. Ring
Keyword(s):  
Heat Treatment ◽  
Thermal Decomposition ◽  
Thermal Treatment ◽  
Treatment Cycle ◽  
Heat Treatment Cycle ◽  
Si3n4 Powder

ABSTRACTA fine white α-Si3N4 powder has been produced by the thermal decomposition of the coprecipitation product of the reaction between SiC14 and NH3. The Cl content, due to a reaction between Si(NH)2 and the NH4Cl by-product during the thermal treatment of the coprecipitate, has been reduced by using an isothermal step at ≈ 250°C in the heat treatment cycle.

Optimization of Heat Treatment Cycles for Automotive Parts Produced by Rheocasting Process

2006 ◽  
Vol 116-117 ◽  
pp. 505-508 ◽  
Author(s):  
Mario Rosso ◽  
Marco Actis Grande
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Performance ◽  
Treatment Cycle ◽  
Total Cost ◽  
Heat Treatment Cycle ◽  
Dimensional Precision ◽  
Heat Treated ◽  
Automotive Parts ◽  
High Level

This work aims at studying the possibility of optimising the heat treatment cycles of parts produced using the New Rheocasting process in order to reduce the total cost of the operation, attaining good mechanical properties for high performance parts. The mechanical properties and the microstructure features of the considered A 356 alloy and the relative produced parts have been analysed and studied on samples machined both from the as cast and from the heat treated compomnents. The obtained results showed the possibility of successfully modifying the T6 heat treatment cycle with economical benefits, maintaining at the same time comparable high level properties and performances, together with good dimensional precision.

High Magnetic Field Annealing of Mn-Ga Intermetallic Alloys

MRS Advances ◽  
2015 ◽  
Vol 1 (3) ◽  
pp. 227-233 ◽  
Author(s):  
Daniel R. Brown ◽  
Ke Han ◽  
Theo Siegrist ◽  
Tiglet Besara ◽  
Rongmei Niu
Keyword(s):  
Magnetic Field ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Permanent Magnets ◽  
Intermetallic Alloys ◽  
Nanostructured Composite ◽  
Refined Microstructure ◽  
Field Annealing ◽  
High Magnetic Moment ◽  
Hard Magnetic Properties

AbstractMn-Ga alloys have shown promising hard magnetic properties, even though these alloys contain no rare-earth metals. However, much work is needed before Mn-Ga alloys become viable permanent magnets for applications. One of the challenges is to enhance the remanence. One technique to improve this property is applying a magnetic field during the heat treatment process. Magnetic annealing can promote phase transformation of the phases with high magnetic moment. This results in an increased remanence. Bulk samples of Mn-Ga alloys were made by mechanically alloying in order to create a nanostructured composite, followed by heat treatments in the presence of a 31 T magnetic field. The heat treatment temperatures were kept low in order to keep the refined microstructure. All the alloys exhibit hard magnetic properties at room temperature with large coercivity. This work reports findings of magnetic field annealed Mn-Ga bulk that exhibit high coercivities up to 19.4 kOe and increased remanence of 50% over the binary system, achieving values up to 6.9 emu/g. This is the highest coercivity reported in bulk Mn-Ga samples.

Role of Heat Treatment in Magnetic Properties of Fe-Co-Ni-Al-Cu-Ti Alloy

2012 ◽  
Vol 510-511 ◽  
pp. 394-398 ◽  
Author(s):  
S. Imran ◽  
M.S. Awan ◽  
M.N. Sarwar ◽  
S. Akhtar ◽  
M. Farooque
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Single Phase ◽  
Permanent Magnets ◽  
X Ray ◽  
Casting Technique ◽  
Alloy Casting ◽  
The Matrix ◽  
Metallurgical Structure

Anisotropic (Fe-24Co-15Ni-7.5Al-3Cu-0.3Ti) permanent magnets were prepared by alloy casting technique. Samples were characterized for structural, microstructural and magnetic properties using x-ray diffractrometer (XRD), Scanning electron microscope (SEM) equiped with energy dispersive x-ray spectrometer and DC magnetometer. There is a relation between metallurgical structure and magnetic properties. The magnetic properties of this type of alloy depend on heat-treatment that is controlling the cooling rate in the presence of magnetic field and double aging. How magnetic properties vary with heat treatment is discussed in this work. XRD studied revealed that the alloy was single phase (bcc) with (110) as the major crystallographic plane. Optical and SEM micrographs showed the presence of (Ti,S)-rich precipitates which are randomly distributed in the matrix. Their composition was analyzed by EDX analysis.

The effect of different heat treatment cycle on hot corrosion and oxidation behavior of Ti–6Al–4V

2019 ◽  
Vol 6 (11) ◽  
pp. 116599 ◽  
Author(s):  
F Sharifi ◽  
V Abouei ◽  
A Alizadeh ◽  
Y Shajari ◽  
M Porhonar ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hot Corrosion ◽  
Oxidation Behavior ◽  
Treatment Cycle ◽  
Heat Treatment Cycle ◽  
Corrosion And Oxidation
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