Phase Transformations in Co5Sm

1973 ◽  
Vol 31 ◽  
pp. 186-187
Author(s):  
P. Rao ◽  
J.G. Smeggil ◽  
E.F. Koch
Keyword(s):  
Heat Treatment ◽  
Phase Transformations ◽  
Optical Metallography ◽  
High Quality ◽  
Temperature Range ◽  
Heat Treated ◽  
Eutectoidal Decomposition

Much higher magnetic coercivities than were previously available have been attained with the compound Co5Sm. However, coercivity is very sensitive to heat treatment; in particular, annealing near 750°C substantially reduces coercivity. This has been attributed to a possible eutectoidal decomposition of Co5Sm into CO17Sm12 and CO7Sm12 on the basis of optical metallography. This possibility makes it necessary to obtain basic electron microstructural information from CO5Sm heat treated in this temperature range.High quality Co5Sm crystals were annealed in sealed Mo bombs at 750°C for 10 days. Electron transparent specimens were prepared by ion thinning in a commercialion milling apparatus.

A Study of the Influence of Local Heat Treatment on the Structure of Welded Titanium Pipelines

2021 ◽  
Vol 410 ◽  
pp. 37-41
Author(s):  
Natalia A. Astafeva ◽  
Andrey A. Balanovskiy ◽  
Anna A. Pershina
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Titanium Alloys ◽  
Welded Joints ◽  
Treatment Method ◽  
Local Heat ◽  
Optical Metallography ◽  
Heat Treated ◽  
Weld Structure ◽  
Heat Treatment Method

The article analyzes the results of a study of the influence of zonal heat treatment on the structure of welded joints of pipeline elements made of titanium alloys Ti-3.5Al-1.5Mn. In the manufacture of such structures, the TIG welding method is used to join pipe elements, after which the heat treatment method can be used to relieve residual stresses. The experiments have confirmed the effectiveness of zonal heat treatment preceded by welding. It was revealed that for welded joints made of titanium alloys, heat treatment can stabilize the structure. In experiments conducted by the method of optical metallography, the structure of heat treated and untreated welded joints was investigated. The influence of heat treatment on the weld structure and heat-affected zone was identified.

The Effect of Post Weld Heat Treatment on Mechanical Properties of Friction-Welded Alloy 718 and SNCRW Stainless Steel

2007 ◽  
Vol 26-28 ◽  
pp. 511-514 ◽  
Author(s):  
Nam Yong Kim ◽  
Jeoung Han Kim ◽  
Yu Sik Kong ◽  
Jong Won Yoon ◽  
Jong Taek Yeom ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Joint ◽  
Friction Welding ◽  
Rotation Speed ◽  
Post Weld Heat Treatment ◽  
Alloy 718 ◽  
Temperature Range ◽  
Heat Treated ◽  
Weld Heat

The effect of post weld heat treatment on mechanical properties of friction welded Alloy 718 and SNCRW was investigated. Friction welding tests were carried out at a constant rotation speed and pressure. Optimum friction condition was found to be the friction pressure of 25kg/cm2, friction time of 40sec, upset pressure of 80 kg/cm2, and dwell time of 5sec. After friction welding tests, post weld heat treatments were performed in the temperature range of 500-900°C for 8hrs in order to investigate the microstructure and mechanical properties of weld joint. Specimens with the post weld heat treatment at 720°C for 8hrs show optimal mechanical properties. Residual stress of post weld heat treated specimens was measured to weld joint in the same temperature range. After friction welding tests on samples with a diameter of 80mm, tensile properties of post-weld-heat-treated and non-heat-treated samples were compared.

Plastic Deformation and Thermal Induced Phase Transformation in 2507 Type Super Duplex Stainless Steel

2017 ◽  
Vol 885 ◽  
pp. 184-189 ◽  
Author(s):  
István Mészáros ◽  
Bálint Bögre
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Power Measurement ◽  
Hardness Tester ◽  
Thermoelectric Power Measurement ◽  
Heat Treated ◽  
Δ Ferrite ◽  
Superduplex Stainless Steel ◽  
Eutectoidal Decomposition ◽  
Cold Rolled

The aim of this study was to investigate the effect of the previously applied cold rolling and the latter heat treatment for the eutectoidal decomposition of δ-ferrite in 2507 type superduplex stainless steel (SDSS). The samples were cold rolled at seven different deformation rates which was followed by heat treatment at were 20, 700, 750, 800 and 850 °C temperatures. The rolled and heat treated samples were investigated by hardness tester, AC magnetometer and thermoelectric power measurement. The activation energy of the decomposition was determined by the Arrhenius equation through the results of the AC magnetometer measurement.

scholarly journals Complex Study of Eutectoidal Phase Transformation of 2507-Type Super-Duplex Stainless Steel

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2205 ◽  
Author(s):  
István Mészáros ◽  
Bálint Bögre
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Cold Rolling ◽  
Super Duplex Stainless Steel ◽  
Heat Treated ◽  
Δ Ferrite ◽  
Eutectoidal Decomposition ◽  
Cold Rolled ◽  
Sample Set

The aim of this work was to study expansively the process of the eutectoidal phase transformation of 2507-type super-duplex stainless steel. Three sample sets were prepared. The first sample set was made to investigate the effect of the previous cold rolling and heat treatment for the eutectoidal phase transformation. Samples were cold rolled at seven different rolling reductions which was followed by heat treatment at five different temperatures. The second sample set was prepared to determine the activation energy of the eutectoidal decomposition process using the Arrhenius equation. Samples were cold rolled at seven different rolling reductions and were heat treated at the same temperature during eight different terms. A third sample set was made to study how another plastic-forming technology, beside the cold rolling, can influence the eutectoidal decomposition. Samples were elongated by single axis tensile stress and were heat treated at the same temperature. The results of the first and the third sample sets were compared. The rest δ-ferrite contents were calculated using the results of AC and DC magnetometer measurements. DC magnetometer was used as a feritscope device in this work. Light microscope and electron back scattering diffraction (EBSD) images demonstrated the process of the eutectoidal decomposition. The thermoelectric power and the hardness of the samples were measured. The results of the thermoelectric power measurement were compared with the results of the δ-ferrite content measurement. The accurate value of the coercive field was determined by a Foerster-type DC coercimeter device.

scholarly journals Effect of cold swaging and heat treatment on properties of the P/M 91W-6Ni-3Co heavy alloy

2008 ◽  
Vol 40 (3) ◽  
pp. 319-331 ◽  
Author(s):  
B. Katavic ◽  
M. Nikacevic ◽  
Z. Odanovic
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Ultimate Strength ◽  
Heavy Alloy ◽  
Temperature Range ◽  
Rotary Swaging ◽  
Cooling Conditions ◽  
Heat Treated ◽  
Toughness Testing ◽  
Reduction In Area

This paper describes the effects of rotary swaging and heat treatment under different conditions on mechanical properties and microstructure of the P/M 91W-6Ni-3Co alloy. The investigation was performed on cold rotary swaging rods with 10, 20 and 25% reduction in area, heat treated at 11300C for 90min under different cooling conditions and strain-aged at temperatures from 300 to 8000C for 60, 180 and 360min. Tensile and toughness testing of rotary swaging rods showed that increase in the reduction resulted in intensive strengthening and toughness lowering. The results of tensile and toughness testing of heat treated rods have shown a decrease in strength, ductility and partly toughness in comparison with the mechanical properties of swaged alloys. The results of strain aged rods demonstrate that, for this cold rotary swaging alloy, there is a temperature range from 500 to 6000C for 60min in which the maximum ultimate strength and hardness may be attained.

Effect of Heat Treatment at (β+γ) Two Phase Region on Fracture Toughness in TiAl Intermetallic Compound

2019 ◽  
Vol 810 ◽  
pp. 21-26
Author(s):  
Makoto Hasegawa ◽  
Tomohiro Inui ◽  
Ivo Dlouhý
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Lamellar Structure ◽  
Treatment Time ◽  
Lamellar Microstructure ◽  
Phase Region ◽  
Two Phase ◽  
Temperature Range ◽  
Heat Treated ◽  
Fully Lamellar

Effects of holding temperature and time at (β+γ) two phase region on the microstructure of fully lamellar Ti-46Al-7Nb-0.7Cr-0.2Ni-0.1Si (mol%) intermetallic compounds are studies. Fully lamellar microstructure is observed after homogenization heat treatment for 3.6 ks at 1643 K (α single phase state). Fine β phased grains precipitate at fully lamellar structure after heat treatment of homogenized material at 1373 K. Holding the homogenized material for 72 ks at 1373 K decompose partially the lamellar structure. Heat treatment of homogenized material at 1273 K also precipitates the fine β phased grains in fully lamellar structure. In this temperature range, decomposition of lamellar structure is not observed up to 72 ks heat treatment. The toughness of homogenized material is ~ 15 MPa√m. Heat treatment of homogenized material at 1373 K and 1273 K for 3.6 ks indicates maximum fracture toughness in each temperature range. This may due to the precipitation of fine β phased grains. The fracture toughness decreases with the increase in heat treatment time up to 18 ks and/or 36 ks. Then, the value of fracture toughness became constant. Specimens heat treated at 1373 K for 36 ks and 72 ks indicate lower toughness than homogenized material. However, when the specimens are heat treated at 1273 K for 36 ks and 72 ks, the toughness is higher than that of homogenized material. This change is due to the decomposition of the lamellar structure.

Influence of Pasteurization and Homogenization Treatments on Photocatalyzed Oxidation of Cream

1977 ◽  
Vol 40 (1) ◽  
pp. 25-28 ◽  
Author(s):  
J. FOLEY ◽  
J. J. GLEESON ◽  
J. J. KING
Keyword(s):  
Heat Treatment ◽  
Lipid Oxidation ◽  
Thioglycolic Acid ◽  
Antioxidant Effect ◽  
Oxidation Catalyst ◽  
Temperature Range ◽  
Heat Treated ◽  
Cysteine Hydrochloride ◽  
Fat Globule ◽  
Sulfhydryl Compounds

Heat treatment within the temperature range of 60 to 94 C promoted photocatalyzed lipid oxidation of cream. The sulfhydryl compounds cysteine hydrochloride, glutathione, thioglycolic acid, and mercapto-ethanol at concentrations of 0.1 to 0.001% acted as antioxidants. Copper migrated from the serum phase to the fat globule surfaces when cream was heated and acted as an oxidation catalyst. The latter influence predominates over the antioxidant effect of the free sulfhydryl groups in heat treated cream. Homogenization of pasteurized cream inhibits lipid oxidation depending on the pressure used.

Thermal Induced Phase Transformations in Duplex Stainless Steel

2012 ◽  
Vol 729 ◽  
pp. 109-113
Author(s):  
István Mészáros
Keyword(s):  
Stainless Steel ◽  
Phase Transformations ◽  
Saturation Magnetization ◽  
Duplex Stainless Steel ◽  
Heat Treatments ◽  
Magnetization Curves ◽  
Microstructural Changes ◽  
Temperature Range ◽  
Heat Treated ◽  
Superduplex Stainless Steel

The aim of this work is to study the microstructural changes in 2507 type superduplex stainless steel due to heat treatments. Two series of specimens were studied. The first series were heat treated isothermally at 800 °C for different times up to 42 minutes. The second ones were heat treated isochronically for 20 minutes in the temperature range of 720-900 °C. The microstuctural changes were investigated by metallography and by magnetic tests. The first magnetization curves and the saturation magnetization loops were measured by a double yoke DC magnetometer.

Effect of a Complex Heat Treatment on the Structure of 300M Steel

1981 ◽  
Vol 39 ◽  
pp. 312-313
Author(s):  
R. Padmanabhan ◽  
W. E. Wood
Keyword(s):  
Heat Treatment ◽  
Metal Carbides ◽  
Austenite Grain Size ◽  
300M Steel ◽  
Heat Treated ◽  
Strain Fracture ◽  
Prior Austenite Grain Size ◽  
Short Time ◽  
Final Tempering ◽  
Similar Yield

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.

A Transmission Electron Microscopical Investigation of Phase Transformations in TiNi

1980 ◽  
Vol 38 ◽  
pp. 340-341
Author(s):  
P. Moine ◽  
G. M. Michal ◽  
R. Sinclair
Keyword(s):  
Electron Microscopy ◽  
Phase Transformations ◽  
Applied Stress ◽  
Structural Changes ◽  
Microscopical Investigation ◽  
Temperature Range ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Diffraction Effects ◽  
Microscopy Images

Premartensitic effects in near equiatomic TiNi have been pointed out by several authors(1-5). These include anomalous contrast in electron microscopy images (mottling, striations, etc. ),diffraction effects(diffuse streaks, extra reflections, etc.), a resistivity peak above Ms (temperature at which a perceptible amount of martensite is formed without applied stress). However the structural changes occuring in this temperature range are not well understood. The purpose of this study is to clarify these phenomena.

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