scholarly journals Influence of the Addition of Ni on as-Cast Microstructure of Duplex Fe-Mn-Al-C Lightweight Steel

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1551
Author(s):  
Jaka Burja ◽  
Barbara Šetina Batič ◽  
Tilen Balaško
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Weight Reduction ◽  
Steel Production ◽  
Microstructural Characterization ◽  
Road Transport ◽  
Thermodynamic Calculations ◽  
Low Density ◽  
Duplex Steels ◽  
Cast Microstructure

Lightweight Fe-Mn-Al-C steels have low density, and high mechanical properties, which makes them a possibility for weight reduction in vehicles for road transport. In steel production, as-cast microstructure is an important parameter for further processing. The as-cast microstructure of five lightweight duplex steels was investigated: Fe-15Mn-10Al-0.8C, Fe-15Mn-10Al-1.7Ni-0.8C, Fe-15Mn-10Al-3.9Ni-0.8C, Fe-15Mn-10Al-5.6Ni-0.8C and Fe-15Mn-10Al-8.6Ni-0.8C. The influence of Ni was analysed through thermodynamic calculations and microstructural characterization. The samples were analysed through an optical and electron microscopy. The base microstructure of the studied steel consists of ferrite and austenite. Further investigation showed that the decomposition of austenite was accompanied by the formation of kappa carbides and the B2 ordered phase. The addition of Ni prevented the formation of a lamellar kappa ferrite morphology, but at 5.6 wt.% Ni, the decomposition of austenite was most severe, resulting in a large amount of kappa carbides and a B2 ordered phase.

scholarly journals Effect of Different Cooling Regimes on the Mechanical Properties of Cementitious Composites Subjected to High Temperatures

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jiangtao Yu ◽  
Wenfang Weng ◽  
Kequan Yu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
High Temperature ◽  
Significant Influence ◽  
Microstructural Characterization ◽  
Cementitious Composite ◽  
Engineered Cementitious Composite ◽  
Before And After ◽  
Scanning Electron

The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of engineered cementitious composite (ECC) subjected to high temperature up to 800°C was discussed in this paper. The ECC specimens are exposed to 100, 200, 400, 600, and 800°C with the unheated specimens for reference. Different cooling regimens had a significant influence on the mechanical properties of postfire ECC specimens. The microstructural characterization was examined before and after exposure to fire deterioration by using scanning electron microscopy (SEM). Results from the microtest well explained the mechanical properties variation of postfire specimens.

Metallographic, Structural and Mechanical Characterization of REM-Containing Fe-30Mn-8Al-1.8C Low Density Steel in As-Cast Condition

MRS Advances ◽  
2018 ◽  
Vol 3 (64) ◽  
pp. 3957-3962
Author(s):  
G.Y. Díaz-Martínez ◽  
I. Mejía ◽  
V. García-García ◽  
A. Bedolla-Jacuinde
Keyword(s):  
Mechanical Properties ◽  
Shape Control ◽  
Research Work ◽  
High Strength Steels ◽  
Microstructural Characterization ◽  
Moderate Increase ◽  
Low Density ◽  
Secondary Phases ◽  
Remarkable Effect ◽  
Cast Condition

ABSTRACTRecently, low-density steels have received increased attention as promising alternatives for automotive applications of the next generation of Advanced High-Strength Steels (AHSS), considering that vehicle´s weight decrease has been the subject of intense interest. It is well-known that the addition of rare earth metals (REM) has a remarkable effect on shape control and the modification of inclusions. Also, REM additions affect the grain size refinement as well as the tendency to form oxides and sulfides. The aim of this research work was to determine the effect of REM (Ce, La) addition on the microstructure and mechanical properties of the Fe-30Mn-8Al-1.8C low-density steel in as-cast condition. In order to clarify the REM effect on the Fe-Mn-Al-C system, non-microalloyed (LD-NM) and REM microalloyed (LD-REM) specimens were examined in detail by means of light optical and scanning electron microscopy for microstructural characterization. In the same way, the primary and secondary phases founded in the studied steels were identified by X-ray diffraction (XRD). Meanwhile, in order to evaluate the mechanical properties, ten microhardness measurements were carried out on the overall bulk by the Vickers hardness testing. In general, the results showed a dendritic refinement effect due to the addition of REM to low-density steel. REM acted as effective inoculants agents which reduced the primary and secondary arm spacing. Also, the strong segregation tendency at the grain boundaries in the liquid phase was limited. XRD profiles revealed the presence of austenite, ferrite, κ and DO3 phases. Low density steel microalloyed with REM showed a moderate increase in hardness compared to the non-microalloyed steel in the as-cast condition.

Effect of Processing Route on Mechanical Behavior of C-Mn Multiphase High Strength Cold Rolled Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4375-4380
Author(s):  
Dagoberto Brandão Santos ◽  
Élida G. Neves ◽  
Elena V. Pereloma
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Quantitative Relationship ◽  
High Strength ◽  
Microstructural Characterization ◽  
Processing Route ◽  
Accelerated Cooling ◽  
Microstructural Parameters ◽  
Transmission Electron

The multiphase steels have complex microstructures containing polygonal ferrite, martensite, bainite, carbide and a small amount of retained austenite. This microstructure provides these steels with a high mechanical strength and good ductility. Different thermal cycles were simulated in the laboratory in order to create the microstructures with improved mechanical properties. The samples were heated to various annealing temperatures (740, 760 or 780°C), held for 300 s, and then quickly cooled to 600 or 500°C, where they were soaked for another 300 s and then submitted to the accelerated cooling process, with the rates in the range of 12-30°C/s. The microstructure was examined at the end of each processing route. The mechanical behavior evaluation was made by microhardness testing. The microstructural characterization involved optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). The use of multiple regression analysis allowed the establishment of quantitative relationship between the microstructural parameters, cooling rates and mechanical properties of the steel.

scholarly journals Research on the Microstructures and Mechanical Properties of Bainite/Martensite Rail Treated by the Controlled-Cooling Process

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3061 ◽  
Author(s):  
Jiajia Qiu ◽  
Min Zhang ◽  
Zhunli Tan ◽  
Guhui Gao ◽  
Bingzhe Bai
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Electron Backscatter Diffraction ◽  
Microstructural Characterization ◽  
Cooling Process ◽  
Controlled Cooling ◽  
Transmission Electron ◽  
Backscatter Diffraction

A bainite/martensite multiphase rail is treated by the controlled-cooling process with different finish-cooling temperatures. The simulated temperature–time curves of the position of 5 mm and 15 mm below the rail tread (P5 and P15) express different trends. P5 has greater impact toughness and lower tensile strength than P15. Microstructural characterization was carried out by conducting scanning electron microscopy, X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy. The greater tensile strength is due to the dispersed ε-carbides hindering the movement of dislocations. The greater impact toughness is attributed to the filmy retained austenite and the smaller effective grain with high-angle boundary. Finite element modeling (FEM) and microstructural characterization reasonably explain the changes of mechanical properties. The present work provides experimental and theoretical guidance for the development of rail with excellent mechanical properties.

scholarly journals Impact of High Temperature on the Compressive Strength of ECC

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xingyan Shang ◽  
Zhoudao Lu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
High Temperature ◽  
Microstructural Characterization ◽  
Cementitious Composites ◽  
Strengthening Effect ◽  
Before And After ◽  
Scanning Electron

The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of ECC (engineered cementitious composites) exposed to high temperature up to 800°C was discussed in this paper. The specimens quenching in water gained better mechanical properties than the ones cooling in air. The strengthening effect of quenching for specimens subjected to 800°C was more significant than for the ones subjected to 400°C. The microstructural characterization is examined before and after exposure to fire deterioration by using scanning electron microscopy. Results from the microtest well explained the mechanical properties variation of postfire specimens.

scholarly journals Effects of Fe-Ions Irradiation on the Microstructure and Mechanical Properties of FeCrAl-1.5wt.% ZrC Alloys

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3423
Author(s):  
Runzhong Wang ◽  
Hui Wang ◽  
Xiaohui Zhu ◽  
Xue Liang ◽  
Yuanfei Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Radiation Doses ◽  
Low Density ◽  
Dislocation Loops ◽  
Transmission Electron ◽  
Fe Ions ◽  
Different Doses

Fe-13Cr-3.5Al-2.0Mo-1.5wt.% ZrC alloy was irradiated by 400 keV Fe+ at 400 °C at different doses ranging from 6.35 × 1014 to 1.27 × 1016 ions/cm2 with a corresponding damage of 1.0–20.0 dpa, respectively, to investigate the effects of different radiation doses on the hardness and microstructure of the reinforced FeCrAl alloys in detail by nanoindentation, transmission electron microscopy (TEM), and atom probe tomography (APT). The results show that the hardness at 1.0 dpa increases from 5.68 to 6.81 GPa, which is 19.9% higher than a non-irradiated specimen. With an increase in dose from 1.0 to 20.0 dpa, the hardness increases from 6.81 to 8.01 GPa, which is an increase of only 17.6%, indicating that the hardness has reached saturation. TEM and APT results show that high-density nano-precipitates and low-density dislocation loops forme in the 1.0 dpa region, compared to the non-irradiated region. Compared with 1.0 dpa region, the density and size of nano-precipitates in the 20.0 dpa region have no significant change, while the density of dislocation loops increases. Irradiation results in a decrease of molybdenum and carbon in the strengthening precipitates (Zr, Mo) (C, N), and the proportionate decrease of molybdenum and carbon is more obvious with the increase in damage.

scholarly journals Microstructural Characterization of the Anisotropy and Cyclic Deformation Behavior of Selective Laser Melted AlSi10Mg Structures

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 825 ◽  
Author(s):  
Mustafa Awd ◽  
Felix Stern ◽  
Alexander Kampmann ◽  
Daniel Kotzem ◽  
Jochen Tenkamp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Selective Laser Melting ◽  
Microstructural Characterization ◽  
Fatigue Tests ◽  
Laser Melting ◽  
Structural Anisotropy ◽  
Scanning Electron

The laser-based fusion of metallic powder allows construction of components with arbitrary complexity. In selective laser melting, the rapid cooling of melt pools in the direction of the component building causes significant anisotropy of the microstructure and properties. The objective of this work is to investigate the influence of build anisotropy on the microstructure and mechanical properties in selective laser melted AlSi10Mg. The alloy is comprehensively used in the automotive industry and has been one of the most frequently investigated Al alloys in additive manufacturing. Using specimens produced in three different building orientations with respect to the build platform, the anisotropy of the microstructure and defects will be investigated using scanning electron microscopy and microcomputed tomography. The analysis showed a seven-times higher pore density for the 90°-specimen compared to the 0°-specimen. The scanning electron microscopy revealed the influence of the direction of the cooling gradient on the constitution of the eutectic phase. Mechanical properties are produced in quasi-static and fatigue tests of variable and constant loading amplitudes. Specimens of 0° showed 8% higher tensile strength compared to 90°-specimens, while fracture strain was reduced almost 30% for the 45°-specimen. The correlation between structural anisotropy and mechanical properties illustrates the influence of the building orientation during selective laser melting on foreseen fields of application.

Microstructural and Mechanical Properties of Ti3Al-Based Intermetallics Produced by Powder Metallurgy

2005 ◽  
Vol 494 ◽  
pp. 211-216 ◽  
Author(s):  
B. Dimčić ◽  
M. Vilotijević ◽  
D. Božić ◽  
D. Rajnović ◽  
M.T. Jovanović
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Room Temperature ◽  
Solution Treatment ◽  
Microstructural Characterization ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

The structural and compression mechanical properties of Ti3Al-based intermetallics produced by powder metallurgy techniques have been studied. The as-milled powders were compacted by hot pressing to non-porous homogenous compacts. Prior to compression tests, all compacts were homogenized by a solution treatment at 1050°C (a+β region) for 1h, followed by water quenching. The compression tests were performed from room temperature to 500°C in vacuum at a strain rate of 1 3 10 4 . 2 − − × s . Detailed microstructural characterization was evaluated by scanning electron microscopy (SEM), followed by energy dispersive spectroscopy (EDS) and X-ray diffraction analysis.

Applications of Core Retraction in Manufacturing Low-Density Polypropylene Foams with Microcellular Injection Molding

2018 ◽  
Vol 37 (1) ◽  
pp. 1-20
Author(s):  
Hrishikesh Kharbas ◽  
Thomas Ellingham ◽  
Lih-Sheng Turng
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Tensile Properties ◽  
Weight Reduction ◽  
Low Density ◽  
Cavity Volume ◽  
The Core ◽  
Process Use ◽  
Incomplete Filling ◽  
Microcellular Injection Molding

Without modifying existing part and mold designs, the conventional microcellular injection molding (MIM) process can typically save about 5–10% material without encountering problems such as incomplete filling, excessive shrinkage, or deteriorating microstructure and mechanical properties. In this study core retraction was used in combination with the MIM process to produce thick polypropylene (PP) parts (up to 7.6 mm thick) with high density reductions of 30% and 55%. The cavity volume was modified by changing the retraction distance, which enabled control of density reductions. The lowest densities were achieved with this core retraction-aided microcellular injection molding (CR-MIM) process, the results of which could not have been achieved by the conventional MIM process alone. The effects of delay time in core retraction and weight reduction on the microstructure of the core and skin layers were investigated. It was shown that the CR-MIM process yielded better microstructure and tensile properties than the conventional MIM process. Use of core retraction also yielded more consistent densities and tensile properties throughout the length of the foamed parts.

Electron Microscopy Techniques for the Microstructural Characterization of Silicon Nitride

1988 ◽  
Author(s):  
Kerry N. Siebein ◽  
Russell L. Yeckley
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Microstructural Characterization ◽  
Ceramic Materials ◽  
Processing Parameters ◽  
Bend Strength ◽  
Fracture Origin ◽  
Microscopy Techniques

It is well known that the mechanical properties of ceramic materials are directly dependent upon their microstructure with respect to the size, crystallinity, distribution and composition of the phases present. Our understanding of the microstructural details of silicon nitride was enhanced through the application of scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). The SEM and STEM are necessary for analyzing the microstructure of silicon nitride because it is a fine grained material. The SEM is used to analyze the etched microstructure and fracture surfaces of bulk silicon nitride samples. Relationships between the grain size distribution, aspect ratio of the grains and fracture toughness of the material are summarized, as well as fracture origin identity and bend strength data. STEM is employed to analyze the crystallinity, distribution and composition of the phases present in a material. These features are related to the processing parameters, fracture toughness and bend strength of silicon nitride. This paper presents a short description of the microscopy techniques employed to characterize silicon nitride, the results obtained using the various techniques and the relationship between the microstructural features and mechanical properties.

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