scholarly journals Enhancing Ductility of 1045 Nanoeutectic Steel Prepared by Aluminothermic Reaction through Annealing at 873 K

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Zhengning Li ◽  
Fuan Wei ◽  
Peiqing La ◽  
Hongding Wang ◽  
Yupeng Wei
Keyword(s):  
Electron Microscope ◽  
Annealing Time ◽  
Volume Fraction ◽  
Cast Steel ◽  
Lamellar Spacing ◽  
Ferrite Matrix ◽  
Aluminothermic Reaction ◽  
Transmission Electron ◽  
Nanocrystalline Ferrite ◽  
1045 Steel

The 1045 steel with lamellar spacing of pearlite in nanometer was prepared by aluminothermic reaction casting and annealed at 873 K (600°C) with different time. Microstructures of steels were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). Tensile properties of the steels were measured. The results showed that the lamellar spacing of the pearlite increased with the annealing time. It was found that the microstructure of steels consisted of nanocrystalline-ferrite matrix and laminar pearlite phase. The average grain sizes of the ferrite were 26.9, 27.0, 26.1, and 34.9 nm for the cast steel and samples annealed for 2, 4, and 6 h, respectively. As the annealing time increased, the volume fraction of the pearlite almost remained constant, while the laminar spacing of pearlite increased from 146 to 300 nm. The tensile and yield strength varied slightly; the elongation obviously improved. After annealing for 4 h, the elongation increased to be 33%, which was the reported highest value for the steel up to now and about twice of the conventional 1045 steel.

Observation of dislocations in dynamically loaded Cu-SiO2

1986 ◽  
Vol 44 ◽  
pp. 424-425
Author(s):  
D. S. Pritchard
Keyword(s):  
Electron Microscope ◽  
Strain Rate ◽  
Single Crystal ◽  
Transmission Electron Microscope ◽  
Volume Fraction ◽  
Screw Dislocations ◽  
Spherical Inclusions ◽  
Transmission Electron ◽  
Crystal Dispersion ◽  
Strain Rate Loading

The effect of varying the strain rate loading conditions in compression on a copper single crystal dispersion-hardened with SiO2 particles has been examined. These particles appear as small spherical inclusions in the copper lattice and have a volume fraction of 0.6%. The structure of representative crystals was examined prior to any testing on a transmission electron microscope (TEM) to determine the nature of the dislocations initially present in the tested crystals. Only a few scattered edge and screw dislocations were viewed in those specimens.

scholarly journals Formation and evolution of porosity during high temperature creep of a nickel-based single crystal superalloy

2020 ◽  
Vol 155 ◽  
pp. 01005
Author(s):  
Weiwei Liu ◽  
Yuanyuan Guo ◽  
Mai Zhang ◽  
Jian Zhang
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Single Crystal ◽  
Volume Fraction ◽  
Great Influence ◽  
Single Crystal Superalloy ◽  
Creep Process ◽  
Steady Creep ◽  
Transmission Electron ◽  
Formation And Evolution

A Re-containing single-crystal superalloy was used to research the high temperature low stress creep behavior. Transmission electron microscope, scanning electron microscope and some other research methods are employed. The results and analysis are summarized below: Two mechanisms for the steady creep are found in this experiment. The volume fraction of pores after creep test at 1100°C increased more than 2 times compared with that before test, but the increasing at 1000°C is relatively small, which reveals that temperature has an great influence on the formation of pore during creep; There are two types of pores associated with fracture during the creep process. One is the casting shrinkage located between the interdentritic, which is formed in the solidification of the alloy. Another type of pore is nucleated and growing during the creep deformation.

Microstructure and Mechanical Properties of Twinning M/A Islands in a X100 High Strength Pipeline Steel

2017 ◽  
Vol 896 ◽  
pp. 182-189 ◽  
Author(s):  
Ji Ming Zhang ◽  
Qiang Chi ◽  
Ling Kang Ji ◽  
Hui Feng ◽  
Yan Hua Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
High Strength ◽  
Pipeline Steels ◽  
Transmission Electron ◽  
Fine Microstructure ◽  
X100 Pipeline Steel ◽  
Deformation Hardening

Fine microstructure of twinning Martensite/austenite (M/A) islands in a X100 high strength pipeline steel were analyzed by the scanning electron microscope (SEM) and high-resolution transmission electron microscope (HRTEM), and a uniaxial compressive experiment of micro-pillar for a twinning M/A island was conducted in present paper. The experimental results showed that M/A islands in X100 pipeline steels were consisted of retained austenite and nanoscale twins with sizes of less than ten nanometers. There were a few small blocks of nanoscale twins in an M/A island. Volume fraction of twinning M/A islands had an important effect on mechanical properties of X100 pipeline steels, with the increase of twinning M/A islands fraction, yield strength of X100 pipeline steel increased, and impact toughness of X100 pipeline steel decreased. The micro-pillar compression showed that the nanoscale twinning M/A island exhibited the higher deformation hardening during the compressive test, and its uniaxial compressive strength could up to 1.35GPa ultrahigh stress level.

Microstructure and Creep Behaviors of As-Cast Mg-Zn-Er Alloys

2017 ◽  
Vol 898 ◽  
pp. 305-310
Author(s):  
Rui Jing Li ◽  
Shu Bo Li ◽  
Ke Liu ◽  
Zhao Hui Wang ◽  
Xian Du ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Creep Strain ◽  
Volume Fraction ◽  
Cast Alloy ◽  
Optical Microscope ◽  
Quasicrystalline Phase ◽  
X Ray Diffraction ◽  
Creep Tests ◽  
Transmission Electron ◽  
Icosahedral Quasicrystalline

The microstructure and creep behaviors of cast Mg-xZn-yEr (x=3,6,9 wt.%, x/y=6) alloys were investigated by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). XRD results indicated that the main phase compositions of as-cast Mg-xZn-yEr alloys were the icosahedral quasicrystalline phase (I-phase) and α-Mg solid solution. The I-phase mainly distributed in the dendritic and staccato strips. The creep tests were conducted under the condition of 448 K, 70 MPa for 100 h. As the addition of Er increased from 0.5 wt.% to 1.5 wt.%, the total creep strain decreased from 0.962% to 0.512%, and the steady state creep rate decreased from 1.411×10-8s-1 to 4.917×10-9s-1. The I-phase had a tendency to be bulky and continuous, as the volume fraction of Er element increased. Ascribed to the I-phase, the creep strain happened and effectively blocked the movement of dislocations, resulting in the strengthened as-cast Mg-Zn-Er alloys and improved creep resistance. Based on the investigation of creep behaviors, the creep mechanism of the as-cast alloy was mainly grain boundary slipping.

MICROSTRUCTURE AND FRACTURE TOUGHNESS OF FeNiCr-TiC COMPOSITE PRODUCED BY THERMITE REACTION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2904-2909
Author(s):  
WENJUN XI ◽  
CHAOLIANG SHI
Keyword(s):  
Fracture Toughness ◽  
Electron Microscope ◽  
Aging Temperature ◽  
Aging Treatment ◽  
Ferrite Matrix ◽  
Β Phase ◽  
Transmission Electron ◽  
The Matrix ◽  
Average Size ◽  
Effects Of Aging

The microstructures of the FeNiCr - TiC composite produced by the rapid solidification thermite process were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The effects of aging treatment on the microstructure and fracture toughness of the composite were examined. Results showed that the FeNiCr - TiC composite was composed of ferrite (α- FeNiCr ), TiC and NiAl (β phase). TiC particles in the matrix were in the shape of polygon and uniformly distributed, and their size was less than 3 µm. The β phase was coherent with the ferrite matrix, and its average size was about 50 nm. The fracture toughness of composite was 22 MPa·m1/2 without aging. When the aging temperature was below 600°C, the fracture toughness of the composite had higher plateau values and reached the maximum of 32 MPa·m1/2 at aging temperature 500°C due to the precipitation of NiAl phase on the nanometer scale. The fracture toughness decreased rapidly aged at 650°C, and then kept homology value in the range of 700 to 900°C, which was attributed to the precipitation of needle-shaped carbide ( Cr / Fe )7 C 3 at the grain boundaries.

Effects of Microstructure on the Fatigue Resistance of Steel Tire Cords

2005 ◽  
Vol 475-479 ◽  
pp. 4125-4128 ◽  
Author(s):  
Yo Sep Yang ◽  
S.Y. Park ◽  
Hyun Jo Jun ◽  
Chan Gyung Park ◽  
S.H. Lim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Content ◽  
Fatigue Resistance ◽  
Volume Fraction ◽  
Lamellar Spacing ◽  
Bending Stress ◽  
Rotating Beam ◽  
Microstructural Parameters ◽  
Transmission Electron ◽  
Points Of View

Effects of microstructural parameters on fatigue resistance (σFL) of the steel tire cords have been investigated experimentally from microscopic points of view. At first, microstructural parameters depending on carbon content have been identified by using transmission electron microscopy (TEM). The fatigue resistance of the steel tire cords depending on carbon content has been measured by using the Hunter rotating beam tester under the bending stress of 900 to 1500 MPa. The fatigue resistance was improved with increasing the carbon content from 0.7, 0.8 to 0.9 wt. % C, due to variations of microstructural parameters, such as lamellar spacing (λp), cementite thickness (tc), and volume fraction (Vc) of cementite. As the carbon content increased, the lamellar spacing and the cementite thickness decreased, while the volume fraction of cementites increased. The effects of microstructure on fatigue resistance have been discussed in terms of the microstructural parameters mentioned above.

Effect of nano BiPb-2212 phase addition on BiPb-2223 phase properties

2018 ◽  
Vol 32 (16) ◽  
pp. 1850178 ◽  
Author(s):  
N. H. Mohammed ◽  
A. I. Abou-Aly ◽  
M. ME. Barakat ◽  
M. S. Hassan
Keyword(s):  
Electron Microscope ◽  
Volume Fraction ◽  
Interlayer Coupling ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Relative Volume ◽  
Fermi Velocity ◽  
Superconducting Transition ◽  
Relative Volume Fraction ◽  
Transmission Electron

BiPb-2212 phase in nanoscale was added to BiPb-2223 phase with a general stoichiometry of (Bi[Formula: see text]Pb[Formula: see text]Sr[Formula: see text]Ca[Formula: see text]Cu[Formula: see text]O[Formula: see text]/Bi[Formula: see text]Pb[Formula: see text]Sr[Formula: see text]Ca[Formula: see text]Cu[Formula: see text]O[Formula: see text], 0.0 [Formula: see text] x [Formula: see text] 2.5 wt.%. All samples were prepared by the standard solid-state reaction method. The prepared nano BiPb-2212 phase was characterized by X-ray powder diffraction (XRD) and transmission electron microscope (TEM). The prepared samples were characterized by XRD and the scanning electron microscope (SEM). XRD analysis indicated that the sample with x = 1.5 wt.% has the highest relative volume fraction for BiPb-2223 phase. Samples were examined by electrical resistivity and I–V measurements. There is no significant change in the superconducting transition temperature [Formula: see text] for all samples. The highest critical current density [Formula: see text] was recorded for the sample with x = 1.5 wt.%. The normalized excess conductivity [Formula: see text] was calculated according to Aslamazov–Larkin (AL) model. Four different fluctuating regions were recorded as the temperature decreased. The coherence length along the c-axis at 0 K [Formula: see text], interlayer coupling strength s, Fermi velocity [Formula: see text] of the carriers and Fermi energy [Formula: see text] were calculated for both samples with x = 0.0 wt.% and 1.5 wt.%.

Microstructural Characterizations of Maraging Steel Processed by Equal-Channel Angular Pressing

2013 ◽  
Vol 745-746 ◽  
pp. 412-416
Author(s):  
M.X. Yang ◽  
Gang Yang ◽  
Z.D. Liu ◽  
C. Wang ◽  
C.X. Huang
Keyword(s):  
Maraging Steel ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Volume Fraction ◽  
Lamellar Spacing ◽  
Electron Backscattered Diffraction ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Refinement Mechanism ◽  
Lamellar Type

Microstructures of a maraging steel subjected to equal-channel angular pressing (ECAP) up to 16 passes at room temperature were investigated. Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) examinations showed that the microstructures of the as-processed samples were characterized by a well-defined lamellar structure. With increasing the number of ECAP passes from 1 to 16, the lamellar spacing was significantly decreased from ~323 nm to ~54 nm, while the volume fraction of high-angle lamellar boundaries (HALBs, having the misorientation larger than 15o) was obviously increased form ~46% to ~80%. The real lamellar-type nanostructured microstructures were completely accomplished in the tested steel after 8 or more ECAP passes. In addition, the grain refinement mechanism of maraging steel during the processing was discussed in detail.

Effect of Heat Treatment on the Microstructure of Cu-Cr-Zr Alloy

2017 ◽  
Vol 727 ◽  
pp. 166-170 ◽  
Author(s):  
Li Jun Peng ◽  
Hao Feng Xie ◽  
Gao Lei Xu ◽  
Guo Jie Huang ◽  
Zhen Yang
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Volume Fraction ◽  
Homogenization Temperature ◽  
Eutectic Structure ◽  
Optical Microscope ◽  
Heat Treatments ◽  
Transmission Electron ◽  
The Matrix ◽  
Zr Alloy

Effect of Heat treatments on microstructure in a Cu-0.71Cr-0.12Zr alloy (in wt.%) have been investigated. The microstructures are analyzed by optical microscope, scanning electron microscope, transmission electron microscope and high-resolution transmission electron microscope after each step of heat treatments. The results show that the as-cast microstructure of Cu-Cr-Zr alloy is Cu matrix, Cr dendrite and eutectic structure which is composed of Cu and Cu5Zr phase with a fine lamellar structure. By increasing the homogenization temperature or prolonging the holding time, the eutectic structure is dissolved into the matrix gradually and the volume fraction of the Cr phases is obviously reduced. The precipitation of Cr phase prevents from Zr-rich phases dissolving in the matrix. And the proper homogenizing process is 900°C×12 h. When the alloy aged at 450°C for 24 h, the crystallography of Cr precipitates and the orientation relationship between Cr precipitates and Cu matrix is bcc structure and KS-OR, respectively. The disk-shaped precipitate is identified as Cu5Zr phase and their habit plane is parallel to {111}Cu plane.

Quantitative Ultrastructural Study of Cat Abducens Interneurons

1992 ◽  
Vol 101 (8) ◽  
pp. 691-698
Author(s):  
Michael J. Lyon ◽  
Brian P. Maloney ◽  
Richard R. Gacek
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Young Adult ◽  
Volume Fraction ◽  
Qualitative Difference ◽  
Cell Types ◽  
Oculomotor Nucleus ◽  
Transmission Electron ◽  
Adult Cats ◽  
Types Of Interneurons

Abducens interneurons project to the medial rectus subdivision of the contralateral oculomotor nucleus and have a role in the mediation of horizontal conjugate gaze. Two types of interneurons have been reported based on shape (fusiform and circular) and differences in organelles. In this study, 41 abducens interneurons from three young adult cats were examined in the transmission electron microscope and were classified, on the basis of eccentricity (e), as circular (e < 0.82; N = 18) or fusiform (e ≥ 0.82; N = 23). The volume fraction of nucleus, nucleolus, mitochondria, rough endoplasmic reticulum, polyribosomes, and Golgi complex and the number of synaptic profiles per 100 μm of membrane were determined. Although there is a qualitative difference in these cell types, statistical analyses indicate no significant differences in organelle content, mean area, number of synaptic profiles per 100 μm of membrane, or diameter. While the differences in shape may possibly indicate different functional groups, this notion is not supported by the variables examined or by physiological studies.

Sign in / Sign up

Export Citation Format

Share Document