scholarly journals Influence of Partial Replacement of Si by Al on Microstructure and Properties of Nanostructured Martensitic Steel

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3718
Author(s):  
Hua Zheng ◽  
Feng Hu ◽  
Wen Zhou ◽  
Oleg Isayev ◽  
Oleksandr Hress ◽  
...  
Keyword(s):  
Retained Austenite ◽  
Volume Fraction ◽  
Strain Curve ◽  
Partial Replacement ◽  
Martensitic Steels ◽  
Stress Strain Curve ◽  
Transformation Induced Plasticity ◽  
Microstructure And Properties ◽  
Lower Volume Fraction ◽  
Lower Volume

Nanostructured martensitic steels comprising nanoscale-martensite and retained austenite were obtained by quenching–partitioning–tempering (Q–P–T) treatment. The influence of partial replacement of Si by Al on the microstructure and properties were studied. Results showed that with partial replacement of Si by Al, except nanoscale-martensite and retained austenite, a little ferrite was also clearly observed. By contrast, with partial replacement of Si by Al, although the ultimate tensile strength (1392 MPa against 1215 MPa) was slightly lower, the elongation after fracture (16.7% against 19.9%) and the toughness (equivalent to the area under the stress–strain curve) (43.1 × 106 against 37.1 × 106 J/m3) were relatively higher. This was because the retained austenite in the steel with partial replacement of Si by Al had higher carbon content, similar volume fraction of film-like morphology, lower volume fraction of blocky morphology and was surrounded by ferrite, which played significant role in the transformation-induced plasticity (TRIP) effect.

The Study on Microstructural and Optical Properties of Nanocrystalline Germanium Films

2010 ◽  
Vol 663-665 ◽  
pp. 324-327
Author(s):  
Chao Song ◽  
Rui Huang
Keyword(s):  
Multilayer Structure ◽  
Room Temperature ◽  
Multilayer Film ◽  
Volume Fraction ◽  
Raman Scattering Spectroscopy ◽  
Force Microscopy ◽  
Room Temperature Photoluminescence ◽  
Atomic Force ◽  
Lower Volume Fraction ◽  
Lower Volume

The germanium film and Ge/Si multilayer structure were fabricated by magnetron sputtering technique on silicon substrate at temperatures of 500°C. Raman scattering spectroscopy measurements reveal that the nanocrystalline Ge occurs in both kinds of samples. Furthermore, from the atomic force microscopy (AFM) results, it is found that the grain size as well as spatially ordering distribution of the nc-Ge can be modulated by the Ge/Si multilayer structure. The room temperature photoluminescence was also observed in the samples. However, compared with that from the nc-Ge film, the intensity of PL from the nc-Ge/a-Si multilayer film becomes weaker, which is attributed to its lower volume fraction of crystallized component.

Formabilities of C-Si-Al-Mn Transformation-Induced Plasticity-Aided Martensitic Sheet Steel

2016 ◽  
Vol 838-839 ◽  
pp. 546-551
Author(s):  
Junya Kobayashi ◽  
Yumenori Nakashima ◽  
Koh Ichi Sugimoto ◽  
Goroh Itoh
Keyword(s):  
Tensile Strength ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Lath Martensite ◽  
Sheet Steel ◽  
Void Formation ◽  
High Volume ◽  
Stress Concentrations ◽  
Transformation Induced Plasticity ◽  
Al Content

The substitution of Si with Al in 0.2%C-1.5%Si-1.25%Mn-0.2%Cr ultrahigh strength transformation-induced plasticity (TRIP)-aided martensitic (TM) sheet steel improves galvanization. The effect of Al content on the microstructure and formabilities of the TM steel was therefore investigated. Replacement of Si with Al maintained the high volume fraction of the retained austenite and the high stretch-formability and stretch-flangeability, whereas it decreased the tensile strength. Complex addition of Si and Al yielded the best formabilities with 1.5 GPa tensile strength grade. The superior formabilities of Si-Al bearing TM steel were attributed to the strain-induced transformation of the metastable retained austenite and the relatively soft lath-martensite structure matrix. The former leads to plastic relaxation of the localized stress concentrations, thus suppressing void formation.

Effect of the Heat Input in the Transformation of Retained Austenite in Advanced Steels of Transformation Induced Plasticity (TRIP) Welded with Gas Metal Arc Welding

2013 ◽  
Vol 339 ◽  
pp. 700-705 ◽  
Author(s):  
Victor Lopez ◽  
Arturo Reyes ◽  
Patricia Zambrano
Keyword(s):  
Heat Input ◽  
Arc Welding ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Residual Austenite ◽  
Welding Parameters ◽  
Transformation Induced Plasticity ◽  
Metal Arc Welding

The effect of heat input on the transformation of retained austenite steels transformation induced plasticity (TRIP) was investigated in the heat affected zone (HAZ) of the Gas Metal Arc Welding GMAW process. The determination of retained austenite of the HAZ is important in optimizing the welding parameters when welding TRIP steels, because this will greatly influence the mechanical properties of the welding joint due to the transformation of residual austenite into martensite due to work hardening. Coupons were welded with high and low heat input for investigating the austenite transformation of the base metal due to heat applied by the welding process and was evaluated by optical microscopy and the method of X-Ray Diffraction (XRD). Data analyzed shows that the volume fraction of retained austenite in the HAZ increases with the heat input applied by the welding process, being greater as the heat input increase and decrease the cooling rate, this due to variation in the travel speed of the weld path.

scholarly journals An Experimental Validation Study of Ferrofluid Evaporation

2021 ◽  
Author(s):  
Wenjuan YU ◽  
Decai Li ◽  
Sifang Niu
Keyword(s):  
Base Fluid ◽  
Experimental Validation ◽  
Magnetic Particles ◽  
Evaporation Rate ◽  
Volume Fraction ◽  
Test Tube ◽  
Weight Losses ◽  
Lower Volume Fraction ◽  
Lower Volume ◽  
The Magnetic Field

Abstract Kerosene based ferrofluid was put into a test tube to evaporate under different conditions. The weight losses of samples were measured and the evaporation rates were calculated. The predictions of evaporation rates were made based on Bolotov’s model. It was found that the magnetic particles prevent the base fluid from evaporation and lower volume fraction leaded to higher evaporation rate. Bolotov’s model had a certain deviation but still well responsive to different variables. It was also found that the magnetic field made a difference to the evaporation rate.

Dielectric Behavior of Barium Titanate/Carbon Fibers Composites

2017 ◽  
Vol 898 ◽  
pp. 2101-2106
Author(s):  
Zhong Yang Wang ◽  
Xin Yan Li ◽  
Run Hua Fan ◽  
Pei Tao Xie ◽  
Kai Sun ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Carbon Fibers ◽  
Percolation Theory ◽  
High Dielectric Constant ◽  
Volume Fraction ◽  
Dielectric Behavior ◽  
Lower Volume Fraction ◽  
Lower Volume ◽  
High Dielectric

Conductor–insulator composites have been extensive researched for high dielectric constant. Most of them concentrated on metal polymers or metal ceramics. Barium titanate–carbon fibers composites were prepared by using a solid state reaction process with carbon fibers contents ranging from7 vol% to 23 vol%. Due to the high-aspect-ratio of carbon fiber, it was easy to produce a conducting network at much lower volume fraction. FESEM images illustrated that the carbon fibers influenced the densification and microstructure of the ceramics. Besides, addition of carbon fibers led to increase in dielectric permittivity, also had effects on the dielectric loss and ac conductivity. The dielectric and conductivity properties as a function of carbon fibers volume fraction were explained by the percolation theory.

HAYNES® 282™ Alloy: A New Wrought Superalloy Designed for Improved Creep Strength and Fabricability

2006 ◽  
Author(s):  
L. M. Pike
Keyword(s):  
Thermal Stability ◽  
Creep Strength ◽  
Volume Fraction ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gamma Prime ◽  
Lower Volume Fraction ◽  
Structural Applications ◽  
Lower Volume ◽  
Prime Phase

A new wrought, gamma-prime strengthened superalloy, HAYNES 282 alloy, has been developed for high temperature structural applications, especially those in aero and land-based gas turbine engines. The new alloy possesses a unique combination of creep strength, thermal stability, and fabricability not found in currently available commercial alloys. The new alloy has excellent creep strength in the temperature range of 1200 to 1650°F (650 to 900°C), surpassing that of Waspaloy alloy and approaching that of R-41 alloy. This level of creep strength is realized despite the alloy having a significantly lower volume fraction of the strengthening gamma-prime phase. The lower gamma-prime content of the new alloy provides a considerable improvement in terms of fabricability and resistance to strain-age cracking, a problem often associated with this class of alloys. In this paper, the major characteristics and attributes of the new alloy including mechanical properties, oxidation resistance, thermal stability, and weldability are presented.

Transformation Induced Plasticity (TRIP) Effect Used in Forming of Carbon CMnSi Steel

2005 ◽  
Vol 500-501 ◽  
pp. 461-470 ◽  
Author(s):  
Jiří Kliber ◽  
Bohuslav Mašek ◽  
Ondrej Zacek ◽  
H. Staňková
Keyword(s):  
Continuous Casting ◽  
Hot Rolling ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
High Strength ◽  
Ferrite Matrix ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Forming Temperature

Transformation induced plasticity (TRIP) steel combines high strength and high ductility that makes it particularly suitable for forming. Martensite within a ferrite matrix is usually obtained either by continuous casting of slabs followed by hot rolling (which is the fastest method, hence the most economical one, producing, however, relatively thick products) or by the continuous casting of slabs followed by hot rolling, cold rolling and annealing (the method used for thin products). High cooling rates, low coiling temperatures and low reduction during hot deformation were generally found to suppress the formation of polygonal ferrite and promote the presence of retained austenite. This paper focuses on development and modifications of two CMnSi-based TRIP steels with 0,23 % C;1,4 % Mn; 1,9 % Si; ( 0,08 % Nb) by means of laboratory thermomechanical processing. Description of experimental devices for the analysis of transformation plasticity under tensioncompression loading is given. Experiments were carried out on the simulator for thermaldeformation cycles SMITWELD and TANDEM was used for thermomechanical processing on the laboratory rolling mill. The maximum volume fraction of retained austenite and the resulting optimum combination of tensile strength and ductility were achieved in testing heats. Special attention was paid to volume fraction changes of single phases and to changes in morphology of phases. The results suggest that rather short isothermal bainite transformation times are sufficient to obtain TRIP microstructure. The influence of parameters of thermomechanical processing such as the amount of strain, forming temperature and austenitization time and temperature on microstructures of TRIP steels were evaluated.

Polypropylene Fiber Reinforced Concrete for Airfield Pavements:Modeling of Stress-Strain Curve Under Compression

2011 ◽  
Vol 261-263 ◽  
pp. 171-177
Author(s):  
Tammam Merhej ◽  
De Cheng Feng
Keyword(s):  
Reinforced Concrete ◽  
Analytical Model ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Strain Curve ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Polypropylene Fiber Reinforced Concrete

An analytical model for compressive stress-strain curve of polypropylene fiber reinforced concrete (PPFRC) was proposed. The polypropylene fiber used was 60-mm long twisted fiber with aspect ratio of 120. The fiber was added in three volume fractions 0.2%, 0.4% and 0.6%. Tow concrete mixtures with varying water-cement ratio were used. The accuracy of the proposed model was evaluated by comparing the area under stress-strain curves for experimental and analytical model. The results showed good agreement between the experimental and analytical curves. In addition; empirical equations were proposed to quantify the effect of polypropylene fiber on compressive strength, strain at peak stress, and toughness of concrete in terms of fiber volume fraction.

Effect of Phosphorus on Microstructure, Mechanical Properties, and Formation of Retained Austenite in TRIP Steels

2012 ◽  
Vol 508 ◽  
pp. 128-132 ◽  
Author(s):  
Eui Pyo Kwon ◽  
Shun Fujieda ◽  
Kozo Shinoda ◽  
Shigeru Suzuki
Keyword(s):  
Mechanical Properties ◽  
Carbon Concentration ◽  
Trip Steel ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
The Stability

In this Study, Influences of P on the Microstructure, Mechanical Properties, and Retained Austenite Characteristics in Transformation Induced Plasticity (TRIP) Steels Were Investigated. Microstructure of 0.2mass%P Containing TRIP Steel Was Inhomogeneous and it Resulted in Deterioration of the Mechanical Properties. Retained Austenite Characteristics such as Volume Fraction and Carbon Concentration Were Also Affected by P. The Stability of Retained Austenite in P Containing TRIP Steel Was Different from that in P-Free TRIP Steel. Such Difference in the Stability of Retained Austenite Was Attributed to the Effect of the Carbon Concentration in Retained Austenite as Well as their Different Microstructure.

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