Microstructural formation, deformation behaviour and deformability of heat treatment steels in the two-phase region

2000 ◽  
Vol 97 (5) ◽  
pp. 589-598
Author(s):  
L. Chabbi ◽  
W. Lehnert
Keyword(s):  
Heat Treatment ◽  
Deformation Behaviour ◽  
Phase Region ◽  
Two Phase

Heat Treatment Recycling of Dual Phase Region and its Effect on Hardness, Microstructure and Corrosion Rate of Medium Carbon Steel

2014 ◽  
Vol 909 ◽  
pp. 100-104
Author(s):  
Mohamed A. Gebril ◽  
M.S. Aldlemey ◽  
Farag I. Haider
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Phase Region ◽  
Medium Carbon Steel ◽  
Dual Phase ◽  
Two Phase ◽  
Medium Carbon ◽  
The Third ◽  
Hardness Increase

In this work, the investigations were carried out to study the effect of heat treatment at dual phase of austenite and ferrite on mechanical properties , microstructure and corrosion rate of low alloyed medium carbon steel. The specimens were divided into five groups, first group, specimens were heated to the duel phase region at temperature of 740°C soaked for 30 minutes and quenched in water. The second group, The specimens were heated to 740°C soaked for 30 minutes and quenched in water, then tempered to 480°C soaked for 20 minutes. The third group the specimens were heated to austenizing temperature of 840°C soaked for 30 minutes and quenched in water, then the specimens reheated to the dual phase region at 740°C, soaked for 30 minutes and quenched in water, then the specimens were tempered at temperature 480°C for 30 minutes. The forth group, the specimens were heated to austenizing temperature of 840°C soaked for 30 minutes and quenched in water, this process were repeated again before the specimens were thereafter heated to the dual phase region at temperature of 740°C, soaked for 20 minutes and quenched in water, then the specimens were tempered at temperature 480°C for 20 minutes. The fifth group, the specimens were heated to austenizing temperature of 840°C soaked for 20 minutes and quenched in water, this process were repeated two times again before the specimens were thereafter heated to the dual phase region at temperature of 740°C, soaked for 20 minutes and quenched in water, then the specimens finally tempered at temperature 480°C for 20 minutes. The results proved the hardness increase after heat treatment at first and second group, at third group the highest hardness value was due to formation of martensite and ferrite, but at fourth and fifth groups hardness decreases due to appearance of carbides particles, also corrosion rate usually increases with two phase at microstructure than stable one phase, third group have less corrosion rate than fourth and fifth due to carbides particles formation which lead to more corrosion rate due to three phases presents.

Tensile Property Improvements of Spinodal Cu-15Ni-8Sn by Two-Phase Heat Treatment

1982 ◽  
Vol 104 (3) ◽  
pp. 234-240 ◽  
Author(s):  
T. J. Louzon
Keyword(s):  
Heat Treatment ◽  
Single Phase ◽  
Phase Region ◽  
Two Phase ◽  
Heat Treated ◽  
Slow Kinetics ◽  
Increased Strength ◽  
Kinetics Of ◽  
Phase Solution ◽  
Strength And Ductility

A heat treatment has been developed which produces significant improvements in the tensile properties of Cu-15Ni-8Sn spinodal alloy. The treatment involves solution heat treatment in the two-phase region rather than the single-phase region normally used. After quenching and aging, increased strength and ductility of the alloy over single phase solution heat-treated and aged values were found. The mechanical properties obtained were superior to any previously observed for material of the compositions studied in the solution treated, quenched, and aged condition. Also, the alloys’ transformation kinetics were greatly slowed by the two phase heat-treatment. It is suggested that the increase in strength and slow kinetics of transformation observed are caused by grain size effects and by grain boundary modifications. Resistivity data and etching response corroborate these arguments.

scholarly journals Improving the Tensile Properties of Additively Manufactured β-Containing TiAl Alloys via Microstructure Control Focusing on Cellular Precipitation Reaction

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 809
Author(s):  
Ken Cho ◽  
Hirotaka Odo ◽  
Keisuke Okamoto ◽  
Hiroyuki Y. Yasuda ◽  
Hirotoyo Nakashima ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Boundaries ◽  
Tensile Properties ◽  
Volume Fraction ◽  
Lamellar Spacing ◽  
Phase Region ◽  
Precipitation Reaction ◽  
Two Phase ◽  
Cellular Precipitation ◽  
High Temperature Tensile

The effect of a two-step heat treatment on the microstructure and high-temperature tensile properties of β-containing Ti-44Al-4Cr (at%) alloys fabricated by electron beam powder bed fusion were examined by focusing on the morphology of α2/γ lamellar grains and β/γ cells precipitated at the lamellar grain boundaries by a cellular precipitation reaction. The alloys subjected to the first heat treatment step at 1573 K in the α + β two-phase region exhibit a non-equilibrium microstructure consisting of the α2/γ lamellar grains with a fine lamellar spacing and a β/γ duplex structure located at the grain boundaries. In the second step of heat treatment, i.e., aging at 1273 K in the β + γ two-phase region, the β/γ cells are discontinuously precipitated from the lamellar grain boundaries due to excess Cr supersaturation in the lamellae. The volume fraction of the cells and lamellar spacing increase with increasing aging time and affect the tensile properties of the alloys. The aged alloys exhibit higher strength and comparable elongation at 1023 K when compared to the as-built alloys. The strength of these alloys is strongly dependent on the volume fraction and lamellar spacing of the α2/γ lamellae. In addition, the morphology of the β/γ cells is also an important factor controlling the fracture mode and ductility of these alloys.

Role of Equiaxed Primary Alpha (α׳) and Mechanical Properties of Ti-6Al-4V Alloy

2012 ◽  
Vol 510-511 ◽  
pp. 420-428
Author(s):  
A. Ahmad ◽  
A. Ali ◽  
G.H. Awan ◽  
K.M. Ghauri ◽  
R. Aslam
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Volume Fraction ◽  
Lamellar Microstructure ◽  
Phase Region ◽  
Bimodal Microstructure ◽  
Two Phase ◽  
Primary Alpha ◽  
Fully Lamellar

The paper presents the role of equiaxed α׳ in the bimodal microstructure to attain an optimal combination of ductility and strength. The study revealed that the production of bimodal microstructure and volume fraction of equiaxed α׳ were reliant on the forging temperature and subsequent heat treatment. The Ti-6Al-4V alloy was forged in the two phase region and different heat treatment cycles were employed to get the desired bimodal microstructure and thus the combination of strength and ductility. The mechanical properties of fully lamellar microstructure were compared with bimodal microstructure containing equiaxed α׳. The experimental results showed that the amount of equiaxed α׳ in the bimodal microstructure was critical for achieving a well-balanced profile of mechanical properties.

Effect of Heat Treatment Temperature-Rate Parameters on Structure and Complex of Physical-Mechanical Properties in VST5553 Titanium Alloy Rod Semi-Finished Goods

2017 ◽  
Vol 265 ◽  
pp. 785-788
Author(s):  
A.V. Zhelnina ◽  
A.G. Illarionov ◽  
M.S. Kalienko
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Cooling Rate ◽  
High Strength ◽  
Phase Region ◽  
Treatment Temperature ◽  
Structure And Properties ◽  
Heavy Duty ◽  
Two Phase ◽  
Temperature Rate

VST5553 titanium alloy is high strength (α + β) - transition alloy which is used for the production of heavy-duty parts [1]. It is known [2], that the cooling rate changing during the heat treatment can change the phases ratio in the alloy. With regards to the VST5553 alloy, this may be due to different cooling rates over the cross section of large-sized semi-finished goods. This in turn affects a complex of properties. Thus, it is necessary to know the effect of the cooling rate of two-phase region on the structure and properties, particularly the VST5553 alloy. However, the research in this area is not sufficient enough. The present study is devoted to this issue.

scholarly journals Effect of Heat Treatment on Microstructure and Mechanical

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Siyuan ZHAO ◽  
Kaixuan CHEN ◽  
Yalikun WUQIKUN ◽  
Xiaohua CHEN ◽  
Zidong WANG
Keyword(s):  
Heat Treatment ◽  
Hsla Steel ◽  
Energy Dispersive Spectrometer ◽  
Tensile Elongation ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Phase Region ◽  
Yield Ratio ◽  
Two Phase ◽  
Treatment Parameter

In this paper, a Fe-based Mn-Ni–Cr–Mo high strength low alloy (HSLA) steel was prepared by using Vacuum melting, following by hot rolling with 78% deformation and various heat treatment processes. Microstructure were characterized by optical microscope (OM), scanning electron microscope (SEM) equipped with energy dispersive spectrometer. Tensile tests were performed. After direct quenching (Q) from 860℃, the samples were subjected to secondary quenching (L) at different intercritical temperatures within the two-phase region and various tempering temperatures (T). Results show that QLT treatment increases elongation and decreases yield ratio compared with conventional quenching and tempering process (QT). The optimum QLT heat treatment parameter in terms of temperature are determined as Q: 860℃, L: 700℃, and T: 600℃, resulting in the better combined properties with yield strength of 756MPa, tensile strength of 820MPa, tensile elongation of 16.76% and yield ratio of 0.923

Effect of Heat Treatment in Two-Phase Region on Equiaxed Variation Law of TC18 Alloy

2016 ◽  
pp. 543-546
Author(s):  
Liu Ji-xiong ◽  
Ma Hong-gang ◽  
Li Wei ◽  
Li Wei-qing ◽  
Wang Xiao-xiang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Region ◽  
Two Phase

Microstructural Evolution and Mechanical Properties of Al3-based Multi-Phase Alloys

2000 ◽  
Vol 646 ◽  
Author(s):  
Seiji Miura ◽  
Juri Fujinaka ◽  
Rikiya Nino ◽  
Tetsuo Mohri
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Ternary System ◽  
Phase Region ◽  
Quaternary Alloys ◽  
Two Phase ◽  
System A ◽  
Preliminary Study ◽  
Multi Phase ◽  
Bcc Phase

ABSTRACTA preliminary study on the phase relations in Al-Mo-Ti-X quaternary systems in the vicinity of Ti-trialuminide phases is carried out with various additives X= Mn, Cr, Fe, Ni and Ag. In the Al-Mo-Ti ternary system, a bcc-phase field extends from the Ti-Mo edge to high Al region at high temperatures and it equilibrates with a DO22-Al3Ti phase containing a large amount of Mo. It is found that, by additions of X= Mn, Cr, Fe or Ni, an L12-(Al, X)3 Ti phase appears near the two-phase region composed of the DO22-Al3 Ti and bcc phases in the Al-Mo-Ti ternary system. By heat treatment at 1223 K, the bcc phase of quaternary alloys decomposes into the A15-Mo3Al, DO22, L12 and/or σ phases, and no voids are observed. The mechanical properties of these alloys are also investigated by Vickers hardness.

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