Microstructure Evolution in an Advanced High Strength Steel under Continuous Cooling

2021 ◽  
Vol 1016 ◽  
pp. 332-337
Author(s):  
Shang Ping Chen ◽  
Richard Mostert ◽  
Maxim Aarnts

The present work was undertaken to understand the phase transformation behaviour in a third generation steel 0.22C-2.1Mn-1.0Si during continuous cooling. The microstructure at various cooling rates were examined by using different techniques, such as optical microscopy, scanning electron microscopy, dilatation test and X-ray measurement. The results show that the amount of bainite that forms during continuous cooling is limited and there is a bainitic transformation stop temperature for this kind of steels. A continuous cooling transformation diagram of the steel is established.

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Li Zhao ◽  
Jingrun Ran ◽  
Zhan Shu ◽  
Guotian Dai ◽  
Pengcheng Zhai ◽  
...  

Ordered titanate nanoribbon (TNR)/SnO2films were fabricated by electrophoretic deposition (EPD) process using hydrothermally prepared titanate nanoribbon as a precursor. The formation mechanism of ordered TNR film on the fluorine-doped SnO2coated (FTO) glass was investigated by scanning electron microscopy (SEM). The effects of calcination temperatures on the phase structure and photocatalytic activity of ordered TNR/SnO2films were investigated and discussed. The X-ray diffraction (XRD) results indicate that the phase transformation of titanate to anatase occurs at 400°C and with increasing calcination temperature, the crystallization of anatase increases. At 600°C, the nanoribbon morphology still hold and the TiO2/SnO2film exhibits the highest photocatalytic activity due to the good crystallization, unique morphology, and efficient photogenerated charge carriers separation and transfer at the interface of TiO2and SnO2.


2010 ◽  
Vol 03 (03) ◽  
pp. 173-176 ◽  
Author(s):  
YIBO WANG ◽  
HUAJUN SUN ◽  
JING ZHOU ◽  
BO LI ◽  
CHENGYONG ZHANG ◽  
...  

Highly oriented Bi2Fe4O9 nanosheets can be fabricated with Fe(NO3)3 ⋅ 9H2O and Bi(NO3)3 ⋅ 5H2O using the low-temperature hydrothermal method. The as-prepared powders are characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), which exhibit an excellent orientation along the (00l) planes. The leakage current density and dielectric properties of the nanosheet samples are measured by Radiant Precision Workstation and HP4291B Impedance Analyzer, respectively. The effects of NaOH concentration on the phase transformation, sheet size and morphologies of the Bi2Fe4O9 crystallites are studied in this paper.


2015 ◽  
Vol 37 ◽  
pp. 122-131 ◽  
Author(s):  
Zhi Jie Li ◽  
Shi Fa Wang ◽  
Bo Li ◽  
Xia Xiang

FeMnO3 powders were synthesized through a modified polyacrylamide gel route. The gel and the heat treated final powders have been characterized by X-ray diffractometry (XRD), differential scanning calorimetry and thermogravimetric analysis (TG/DSC) and field-emission scanning electron microscopy (SEM). Phase transformation sequence of dry gel during heating is (Mn+3,Fe+3)2O3→(α-Mn2O3)·(α-Fe2O3)→FeMnO3. The thermal expansion properties of as-prepared sample were determined. From 100 to 700 °C, the average coefficient of expansion is 9.0139×10-6 /K. The experimental results demonstrates that the FeMnO3 sample exhibit a ferromagnetic transitions with TN ≈ 40 K.


2015 ◽  
Vol 74 (10) ◽  
Author(s):  
Y. C. Wee ◽  
T. Abubakar ◽  
E. Hamzah ◽  
Safaa N. Saud

The effect of Co addition on phase transformation temperatures and microstructures of Cu-Al-Ni SMA were investigated via differential scanning calorimetry, field emission scanning electron microscopy corresponding with energy dispersive spectroscopy and x-ray diffraction. The results revealed that the β1’ and γ1’ phases’ morphology and orientation were varied after the addition of Co along with the presence of intermetallic compounds known as γ2. This phase was indicated using the EDS and XRD is related to the intermetallic compound of Al75Co22Ni3. In addition, the phase transformation temperatures tend to increase with the addition of Co and this enhancement is mainly attributed to the variation of phase morphology and the existence of γ2 precipitates. 


2014 ◽  
Vol 602-603 ◽  
pp. 499-502 ◽  
Author(s):  
Yuan Yuan Zhu ◽  
Shang Sheng Li ◽  
Liang Li ◽  
Ai Guo Zhou

Ternary carbide Ti3SiC2 is a good binder to make superhard composites with diamonds or cubic boron nitride. Superhard composites are normally made at high temperature and under high pressure around 5 GPa to avoid the phase transformation of diamonds or cubic boron nitride. This paper researched the synthesis of Ti3SiC2 from the powders of Ti, Si, and graphite by a cubic presser under 1 GPa to 4 GPa at 1400°C. The decomposition of Ti3SiC2 under 5GPa at 1400°C was also researched. From X-ray diffraction (XRD) and scanning electron microscopy (SEM) results, Ti3SiC2 was synthesized in 30 min under 1 GPa at 1400°C. The impurities were TiSi2, Ti5Si3Cx, and TiC. As the pressure increased from 1GPa to 4GPa, less Ti3SiC2 more TiSi2 was synthesized. Therefore, high presser > 1GPa is unfavorable for the synthesis of Ti3SiC2. After treated under 5GPa at 1400°C, pure Ti3SiC2 was decomposed.


2011 ◽  
Vol 409 ◽  
pp. 526-531 ◽  
Author(s):  
L. Monaco ◽  
J.L. McCrea ◽  
G. Palumbo ◽  
Uwe Erb

In this study, alternatives to corrosion-resistant cadmium coatings on high strength steel fasteners are explored. Nanocrystalline Zn-Ni and Zn-Ni-Co electrodeposits, synthesized by electrochemical deposition, were analyzed by potentiodynamic polarization in a 1M NaCl aqueous solution, to determine the corrosion behaviour of the alloys. Sample coatings were characterized using scanning electron microscopy to examine differences in surface morphology that can affect corrosion resistance. Energy dispersive x-ray spectroscopy was used to relate composition to corrosion resistance and to characterize the corrosion behavior during polarization. All coatings showed corrosion potentials at equivalent, or lower values than that of cadmium, suggesting that both alloys are viable as cadmium replacements. Specific compositions showed slightly passivating regions, but the brittle film formed during polarization is unstable. Comparatively, Zn-Ni shows a better resistance to corrosion than Zn-Ni-Co. The effect of composition on the corrosion resistance can be explained on the basis of the sacrificial depletion of Zn over Ni.


2007 ◽  
Vol 336-338 ◽  
pp. 1642-1645 ◽  
Author(s):  
Tong Jun Liu ◽  
De An Yang ◽  
Li Zhi Di

The β-TCP granules with the range of diameter from 314μm to 800μm were prepared. The β-TCP/HAP composite bioceramics were prepared by dipping β-TCP discs made from the granules in HAP sol. The component and morphology of the ceramics were observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The compressive strength of specimens was tested by Testometric M350-20KN. The results show that the samples can be calcined at 1150°C without phase transformation of β-TCP to α-TCP by doping the β-TCP with 1wt% MgO. And the compressive strength of the composite ceramics reaches 24MPa.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Seyed Naser Azizi ◽  
Akram Alavi Daghigh ◽  
Maryam Abrishamkar

In the present study, the synthesis of template free zeolite P under hydrothermal condition was investigated. The effects of parameters such as Si/Al ratios (3–45), crystallization temperatures (80–160°C), and cry (40–60 h) on the synthesis of zeolite P were studied. The phase transformation of zeolite P to two types of high crystallinity Y and analcime zeolites due to change of temperature was observed. The effect of temperature on the achievement of two different zeolite types (Y and analcime) with a constant initial synthetic composition under organic free synthesis of zeolite P was studied. The zeolitic products were characterized by X-ray diffraction, scanning electron microscopy, and IR spectroscopy techniques.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


Author(s):  
M. L. Zimny ◽  
A. C. Haller

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.


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