Microstructural Evolution during Tempering of 16Cr-5Ni Stainless Steel: Effects on Final Mechanical Properties

2013 ◽  
Vol 762 ◽  
pp. 176-182 ◽  
Author(s):  
Massimo De Sanctis ◽  
Renzo Valentini ◽  
Gianfranco Lovicu ◽  
Antonella Dimatteo ◽  
Randa Ishak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Microstructural Evolution ◽  
Maximum Hardness ◽  
X Ray Diffraction ◽  
Structural Behaviour ◽  
X Ray ◽  
Transmission Electron ◽  
Normative Requirements ◽  
Double Tempering

In this work, the structural behaviour during tempering of two different heats of 16Cr-5Ni supermartensitic stainless steel has been studied by means of dilatometry, transmission electron microscopy and X-ray diffraction. A thermomechanical simulator (Gleeble 3800) has been also used to characterize the effects on final mechanical properties of different tempering temperatures in the range 600 °C to 700 °C and the influence of sub-zero cooling on industrial double tempering treatments. It has been found that the pre-existence of retained austenite in as-quenched conditions can induce significant differences in the microstructural evolution during tempering and on the final mechanical properties of industrial components, thus inducing problems in controlling final maximum hardness allowable by normative requirements.

scholarly journals Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Xianjie Yuan ◽  
Xuanhui Qu ◽  
Haiqing Yin ◽  
Zaiqiang Feng ◽  
Mingqi Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Velocity ◽  
Sintered Density ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Velocity Compaction ◽  
Sintered Temperature

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

β Stability and Mechanical Behavior of Metastable β Type TiNb Based Alloys

2013 ◽  
Vol 747-748 ◽  
pp. 941-946
Author(s):  
Guang Yue Liao ◽  
Shun Guo ◽  
Zhen Zhen Bao ◽  
Xin Qing Zhao
Keyword(s):  
Martensitic Transformation ◽  
Mechanical Behavior ◽  
Microstructural Evolution ◽  
Mechanical Test ◽  
Cold Deformation ◽  
Strengthening Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Low Elastic Modulus

Metastable β type TiNb based alloys of Ti-35Nb, Ti-35Nb-4Sn and Ti-42Nb-4Sn (wt. %) with different stability were prepared and thermo-mechanical treatment was carried out to investigate their microstructural evolution and mechanical properties. It was found that although the TiNb based alloy with lower stability performs lower strength in its solution state due to the stress induced martensitic transformation, they could be strengthened significantly by severe cold rolling followed by aging, remaining a relative low elastic modulus. X-ray diffraction, transmission electron microscopy and mechanical test were conducted to characterize the microstructural evolution and mechanical behavior of the metastable β type TiNb based alloys with different β stability. The strengthening mechanism was discussed on the basis of the cold deformation and martensitic transformation.

Biodegradable Nanocomposites of Poly(hydroxybutyrate-co-hydroxyvalerate): The Effect of Nanoparticles

2008 ◽  
Vol 8 (4) ◽  
pp. 1858-1866 ◽  
Author(s):  
Pralay Maiti ◽  
Jaya P. Prakash Yadav
Keyword(s):  
Mechanical Properties ◽  
Layered Silicate ◽  
Layered Silicates ◽  
Thermal And Mechanical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicate Nanocomposites ◽  
Transmission Electron ◽  
Superior Mechanical Properties ◽  
Biodegradable Nanocomposites

Copolymer of hydroxybutyrate and hydroxyvalerate, P(HB-HV)/layered silicate or hydroxyapatite nanocomposites were prepared via melt extrusion. The nanostructure, as observed from wide-angle X-ray diffraction and transmission electron microscopy, indicate intercalated hybrids for layered silicates. Hydroxyapatite of nanometer dimension is uniformly distributed in matrix copolymer. The nanohybrids show significant improvement in thermal and mechanical properties of the copolymer as compared to the neat copolymer. The layered silicate nanocomposites exhibit superior mechanical properties as compared to hydroxyapatite nanohybrid. The thermal expansion coefficient is significantly reduced in nanohybrids. The biodegradability of pure copolymer and its nanocomposites were studied at room temperatures under controlled conditions in compost media. The rate of biodegradation of copolymer is enhanced dramatically in the nanohybrids. Hydroxyapatite hybrid shows highest rate of biodegradation. The change in biodegradation is streamlined in terms of nature of nanoparticles used to prepare hybrids.

The Ti-B-N System: Nanocomposite nc-TiN/a-(TiB2, BN) and Nano-Multilayer nc-TiN/a-TiBN Thin Films

2008 ◽  
Vol 8 (5) ◽  
pp. 2713-2718
Author(s):  
Y. H. Lu ◽  
K. Chu ◽  
Y. G. Shen
Keyword(s):  
Thin Films ◽  
Dislocation Motion ◽  
Structural Barriers ◽  
Mechanical Behaviors ◽  
Bilayer Thickness ◽  
Maximum Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Transmission Electron

The nanostructures and mechanical properties of nanocomposite nc-TiN/a-(TiB2, BN) and nanostructured multilayers nc-TiN/a-TiBN were investigated using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), microindentation, and stress measurements. It was found that the monolayer Ti-B-N thin films consisted of nanometer-sized crystalline (nc-) Ti(N, B) embedded into amorphous (a-) (TiB2, BN) matrix. When B content was below ∼16 at.%, two different-sized nanocrystallites with mean grain sizes of ∼3 and 9 nm respectively were embedded in a-TiB2. With increasing B incorporation (>∼27 at.%), more uniform nanograins was embedded a-(TiB2, BN). Incorporation of B not only decreased the size of nanocrystallites, but also gave rise to twinning deformation in nanocrystallites. A maximum hardness of ∼44 GPa was achieved at B content of 19 at.%. It was also found that the nanostructure and mechanical behaviors of nc-TiN/a-TiBN multilayers was dependent on the modulation length (bilayer thickness Λ). Decrease of Λ made the preferred orientation of nc-TiN gradually transform from (200) to (111). A maximum hardness of ∼30 GPa was achieved at Λ = 1.8 nm. Deflection from this Λ value decreased hardness. By contrast, the residual compressive stress value monotonically increased with decrease of Λ. The enhancement of the hardness was due to the coherent stresses and the structural barriers to dislocation motion in the interface.

scholarly journals Influence of the Double Bond LDH Clay on the Exfoliation / Intercalation Mechanism of Polyacrylamide Nanocomposite Hydrogels

2018 ◽  
Vol 55 (3) ◽  
pp. 263-268
Author(s):  
Ionut Cristian Radu ◽  
Eugeniu Vasile ◽  
Celina Maria Damian ◽  
Horia Iovu ◽  
Paul Octavian Stanescu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
Biomedical Applications ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanocomposite Hydrogels ◽  
Transmission Electron ◽  
Double Hydroxides ◽  
Classical Cross ◽  
Chemical Cross Linking

The paper focuses on the obtaining of novel nanocomposite hydrogels based on polyacrylamide and layered double hydroxides (LDHs) modified with double bonds. The modification of LDH clay was investigated by FTIR, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses. Mechanical properties of the nanocomposite hydrogels were employed by compression and rheological measurements. The formation of exfoliated and intercalated structures was evidenced in transmission electron microscopy (TEM). Chemical cross-linking of hydrogels using both classical cross-linker and modified clay was an efficient method to improve the mechanical properties of novel nanocomposite hydrogels. These hydrogels with improved mechanical properties could be further tested for biomedical applications such as tissue engineering.

scholarly journals Effects of TiO2/SiO2 Reinforced Nanoparticles on the Mechanical Properties of Green Hybrid Coating

2015 ◽  
Vol 47 ◽  
pp. 56-66 ◽  
Author(s):  
Mohammed Gobara
Keyword(s):  
Mechanical Properties ◽  
Sol Gel ◽  
Hardness Test ◽  
Silica Sol ◽  
X Ray Diffraction ◽  
Properties Of Coatings ◽  
X Ray ◽  
Hybrid Silica ◽  
Transmission Electron ◽  
Adhesion Performance

Titanium and silica oxides nanoparticles were introduced into hybrid silica sol–gel/epoxy coating to enhance the mechanical properties of coatings. Titanium dioxide (TiO2) and silica oxide (SiO2) were chemically synthesised before adding to the prepared silica sol gel coating. X-ray diffraction (XRD), Energy-dispersive x-ray analysis (EDX) and Transmission Electron microscope (TEM) were used to characterize the prepared nanoparticles. The coating was then applied to 3003 aluminium alloy (AA3003) surface. The adhesion performance of different sol gel coating compositions was investigated using shear test to define the influence of nanoparticles on adhesive strength of the coating. The Rockwell C hardness test was used to study the micro-hardness of different compositions of sol gel coating. Also, contact angel was used to investigate the hydrophobicity of the coatings. The results showed that there was a significant improvement of the adhesion performance of hybrid silica sol gel coating due to addition of TiO2 and the hydrophobicity of sol gel coating was increased due to addition of SiO2 nanoparticles.

Fullerene-Metal Composites: Phase Transformations During Milling and Sintering

2011 ◽  
Vol 172-174 ◽  
pp. 727-732 ◽  
Author(s):  
Ileana Irais Santana ◽  
Francisco Carlos Robles Hernandez ◽  
Vicente Garibay-Febles ◽  
Hector A. Calderon
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Phase Transformations ◽  
Mechanical Milling ◽  
X Ray Diffraction ◽  
Metal Composites ◽  
X Ray ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

Composites of Fe-C60and Al C60produced by mechanical milling and sinterized by Spark Plasma Sintering are investigated with special attention to the mechanical properties of the products. The processing involves phase transformations of the fullerenes that are interesting to follow and characterize. This involves formation of tetragonal/rhombohedral diamond and carbides during sintering and milling. Transmission Electron Microscopy (TEM) and Raman Spectroscopy techniques are also used to confirm preliminary results of X Ray Diffraction (XRD) related to the formation of nanostructures i.e., grain size of the crystals during mechanical milling and after sintering, spatial distribution of phases and the different phases that are developed during processing.

Transmission electron microscopy of SI-AL-O-N alloys

1978 ◽  
Vol 36 (1) ◽  
pp. 302-303 ◽  
Author(s):  
M. Kirn ◽  
M. Rühle ◽  
H. Schmid ◽  
L.J. Gauckler
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Imaging Technique ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Operating Voltage ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

It is expected that Si-Al-O-N alloys are important high temperature construction materials. The phase diagrams for Si-Al-O-N alloys were studied systematically mainly by X-ray diffraction work (for a summary see). Different stable phases were found. For the understanding of the physical and mechanical properties it is of great interest to know for the different stable phases the microstructure and the morphology, which can be obtained by TEM observations. Results of some TEM studies are reported here utilizing not only the conventional TEM but also the lattice fringe imaging technique.Specimens of the different phases were produced as described in They were prepared for TEM observations. For high resolution work a Siemens ELMISKOP 102 (operating voltage 125 kV) was used fitted with a double tilting stage (± 45°), for conventional TEM studies the specimens were examined in an AEI EM7 high voltage EM operated at 1 MeV.

Prepare of the New Structure PbTiO3 Nanowires and the Study of the Reversible Bending

2013 ◽  
Vol 331 ◽  
pp. 522-526
Author(s):  
Jiang Wang ◽  
Jian Li ◽  
You Wen Wang
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Hydrothermal Reaction ◽  
The Self ◽  
X Ray Diffraction ◽  
Electron Backscattered Diffraction ◽  
X Ray ◽  
Transmission Electron

When the self-made with Teflon lined with stainless steel reaction kettle is used to produce PbTiO3 nanowires with the adoption of hydrothermal reaction , PbTiO3 nanowires with new structure can be made when Pb/Ti equals 2.2. Observed through the Transmission Electron Microscopy (TEM), the bending feature of the PbTiO3 nanowires can be observed for several times when X-ray diffraction (XRD) and Electron Backscattered Diffraction (EBSD) are used to analyse and test the crystal structure of the nanowires. The result of the study shows that the degree of the bending of the PbTiO3 nanowires varies with the intensity of the electron beam from the Transmission Electron Microscopy, and its process can be reversible.

Variation of the Reversed Austenite Amount with the Tempering Temperature in a Fe-13%Cr-4%Ni-Mo Martensitic Stainless Steel

2010 ◽  
Vol 650 ◽  
pp. 193-198 ◽  
Author(s):  
Yuan Yuan Song ◽  
Xiu Yan Li ◽  
Fu Xing Yin ◽  
De Hai Ping ◽  
Li Jian Rong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Low Carbon ◽  
Reversed Austenite ◽  
X Ray Diffraction ◽  
Tempering Temperature ◽  
X Ray ◽  
Transmission Electron

Tempering temperature dependence of the amount of the reversed austenite in the range of 570 oC to 680 oC was investigated by means of X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) in a low carbon Fe-13%Cr-4%Ni-Mo (wt.%) martensitic stainless steel. It was found that the reversed austenite began to form at the tempered temperature slightly above the As temperature. As the tempered temperature increased, the amount of the reversed austenite changed little in the temperature range of 580-595 oC. Then, the amount of the reversed austenite increased sharply with the increased tempered temperature. When the tempered temperature increased to about 620 oC, the amount of the reversed austenite exhibited a peak. Afterward, it decreased quickly at the elevated tempered temperature. The microstructural evolvement of the reversed austenite at different tempering temperature was also observed by TEM.

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