Microstructure and Mechanical Property of Ti3AlC2/TiAl3 Composite Synthesized by Hot Pressing

2015 ◽  
Vol 816 ◽  
pp. 210-215
Author(s):  
Wei Ping Chen ◽  
Yong Zeng ◽  
Xiao Mei Li ◽  
Hua Qiang Xiao
Keyword(s):  
Hot Pressing ◽  
Bending Strength ◽  
Milling Process ◽  
Toughening Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
New Phase ◽  
Microstructure And Mechanical Property

Ti3AlC2/TiAl3 composite was successfully fabricated by ball milling and in-situ reaction/hot-pressing of Ti, Al and graphite powders mixture at 1200 °C and 30 MPa for 30 min. The phase composition and microstructure of the milled powders and synthesized composite were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), the mechanical properties and the toughening mechanism of 20%vol Ti3AlC2/TiAl3 composite was also studied. The results show that no new phase is detected during 50 h of milling process. The in-situ synthesized samples are fully dense and composed of 72%vol TiAl3, 24%vol Ti3AlC2 and 4%vol Al2O3/TiC. The Vickers Hardness, three-point bending strength and fracture toughness of the composite is ~5.2 GPa, ~243 MPa and ~4.3 MPa/m1/2, respectively. Analysis of microstructure reveals that crack deflection, crack bridging and delamination of Ti3AlC2 are the main mechanism responsible for the toughening.

Fabrication of Nano-MgO Reinforced Fe-Cr-Ni Composites by Reactive Hot Pressing

2009 ◽  
Vol 620-622 ◽  
pp. 551-554 ◽  
Author(s):  
Chang Chen ◽  
Jian Feng Yang ◽  
Ji Qiang Gao ◽  
Cong Yang Chu
Keyword(s):  
Hot Pressing ◽  
Low Temperatures ◽  
Bending Strength ◽  
Exothermic Reaction ◽  
X Ray ◽  
Three Point Bending ◽  
Fine Grained ◽  
In Situ Formation ◽  
Reactive Hot Pressing

The self-propagating combustion reaction 0.741Mg + 0.247Fe2O3 + 0.188Ni + 0.318Cr → 0.741MgO + Fe0.494Ni0.188Cr0.318 was applied to prepare a nano-MgO reinforced Fe-Cr-Ni composite, by reactive hot pressing (RHP) under a condition of 700°C/30MPa/2h. The densification was enabled by the low temperatures produced by the exothermic reaction. According to TG-DTA and X-ray diffractometry (XRD), the highly-exothermic thermite reaction began at about 600°C and the in-situ formation of composites comprised predominantly of (FCC) Cr0.19Fe0.7Ni0.11, (FCC) Fe-Cr, (BCC) MgO and a small quantity of (BCC) MgFe2O4. The Vickers hardness was 3.67GPa, the three-point bending strength was 112.5±10MPa, and the fracture toughness was 3.28 MPa•m1/2. The microstructure of the composite was observed via scanning electron microscopy. This indicated that the distributions of in-situ-formed (BCC) MgO phases (~800 nanometers) were homogeneous into in a matrix of a fine-grained metallic alloy phases that gather together to form agglomerates in the composite.

scholarly journals In Situ Coherent X-ray Diffraction during Three-Point Bending of a Au Nanowire: Visualization and Quantification

2018 ◽  
Vol 2 (4) ◽  
pp. 24 ◽  
Author(s):  
Anton Davydok ◽  
Thomas Cornelius ◽  
Zhe Ren ◽  
Cedric Leclere ◽  
Gilbert Chahine ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Reciprocal Space ◽  
X Ray Diffraction ◽  
Complex Deformation ◽  
X Ray ◽  
Three Point Bending ◽  
Atomic Force ◽  
Au Nanowire ◽  
Before And After

The three-point bending behavior of a single Au nanowire deformed by an atomic force microscope was monitored by coherent X-ray diffraction using a sub-micrometer sized hard X-ray beam. Three-dimensional reciprocal-space maps were recorded before and after deformation by standard rocking curves and were measured by scanning the energy of the incident X-ray beam during deformation at different loading stages. The mechanical behavior of the nanowire was visualized in reciprocal space and a complex deformation mechanism is described. In addition to the expected bending of the nanowire, torsion was detected. Bending and torsion angles were quantified from the high-resolution diffraction data.

scholarly journals Fabrication of Silk Resin with High Bending Properties by Hot-Pressing and Subsequent Hot-Rolling

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2716
Author(s):  
Hoang Anh Tuan ◽  
Shinji Hirai ◽  
Shota Inoue ◽  
Alharbi A. H. Mohammed ◽  
Shota Akioka ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Hot Pressing ◽  
Bending Strength ◽  
Decomposition Temperature ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Bending Properties ◽  
X Ray ◽  
Bombyx Mori Silk ◽  
Increased Strength

This research reports the processability and mechanical properties of silk resins prepared by hot-pressing followed by hot-rolling and then analyzes their thermal and structural properties. The results show that regenerated silk (RS) resins are better suited for hot-rolling than Eri and Bombyx mori silk resins (untreated silk). When hot-rolling at 160 °C with a 50% of reduction ratio, maximum bending strength and Young’s modulus of RS resin reaches 192 MPa and 10.2 GPa, respectively, after pretreatment by immersion in 40 vol% ethanol, and 229 MPa and 12.5 GPa, respectively, after pretreatment by immersion in boiling water. Increased strength of the material is attributed to the increased content of aggregated strands and intramolecular linking of β sheets (attenuated total reflectance Fourier-transform infrared spectroscopy) and higher crystallinity (X-ray diffraction analysis). After hot-pressing and hot-rolling, RS resins have a stable decomposition temperature (297 °C).

Fabrication and Mechanical Properties of SiC/Cu Composites with Zn Addition by Hot Pressing Sintering

2013 ◽  
Vol 745-746 ◽  
pp. 700-705
Author(s):  
Huang Liu ◽  
Guo Qiang Luo ◽  
Pin Gan Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
High Volume ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zn Addition ◽  
Hot Pressing Sintering

SiC/Cu composites exhibit low density, low coefficient of thermal expansion and excellent mechanical properties. In this study, Zn of 2 wt. % was added as the sintering activator, and the high volume faction (60%) SiC/Cu composites was fabricated by hot pressing sintering technology. The phase composition and morphology of as-prepare samples were characterized by X-ray diffraction (XRD) system and scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS) system. The as-prepared SiC/Cu composites were dense and uniform as well as void free. The results show that SiC/Cu composites can reach excellent mechanical properties of SiC/Cu composites. With the increase of sintering temperature, Vickers hardness and the bending strength of the samples increased obviously and the as-prepared SiC/Cu composites achieved a maximum Vickers hardness and bending strength respectively of 195MPa and 140MPa.

Fabrication of TiAl/B4C Composites from an Al-Ti-B4C System Reinforced by TiC, TiB2 In Situ

2009 ◽  
Vol 79-82 ◽  
pp. 477-480 ◽  
Author(s):  
Li Hua Dong ◽  
Wei Ke Zhang ◽  
Jian Li ◽  
Yan Sheng Yin
Keyword(s):  
Bending Strength ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
High Energy ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hot Pressing Sintering ◽  
Different Content

Near full dense B4C ceramic matrix composites were fabricated from Ti-Al-B4C system by combining high energy milling with hot pressing sintering. The effect of different content of Ti-Al on the mechanical properties and microstructure of the as-prepared composites was investigated. A TiAl/B4C composite, whose typical bending strength and fracture toughness are 437.3 MPa and 4.85 MPa•m1/2, respectively, was made. The sintering mechanism and reinforcement mechanism were discussed with the assistant of X-Ray diffraction and electron microscopy.

scholarly journals Mechanochemical Knoevenagel condensation investigated in situ

2017 ◽  
Vol 13 ◽  
pp. 2010-2014 ◽  
Author(s):  
Sebastian Haferkamp ◽  
Franziska Fischer ◽  
Werner Kraus ◽  
Franziska Emmerling
Keyword(s):  
Knoevenagel Condensation ◽  
Direct Conversion ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
In Situ Data ◽  
Solvent Free Conditions ◽  
Yield Time

The mechanochemical Knoevenagel condensation of malononitrile with p-nitrobenzaldehyde was studied in situ using a tandem approach. X-ray diffraction and Raman spectroscopy were combined to yield time-resolved information on the milling process. Under solvent-free conditions, the reaction leads to a quantitative conversion to p-nitrobenzylidenemalononitrile within 50 minutes. The in situ data indicate that the process is fast and proceeds under a direct conversion. After stopping the milling process, the reaction continues until complete conversion. The continuous and the stopped milling process both result in crystalline products suitable for single crystal X-ray diffraction.

Preparation and characterization of graphene oxide/PMMA nanocomposites with amino-terminated vinyl polydimethylsiloxane phase interfaces

2016 ◽  
Vol 36 (9) ◽  
pp. 867-875 ◽  
Author(s):  
Hongyan Li ◽  
Weian Wang ◽  
Lin Cheng ◽  
Jing Li ◽  
Yajing Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Bending Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Three Point Bending ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Amidation Reaction

Abstract Graphene oxide (GO) was prepared by the Hummers method and was grafted by an amino-terminated vinyl polydimethylsiloxane (AP). The AP-modified GO (GO-AP) was incorporated in poly(methylmethacrylate) (PMMA) to prepare nanocomposites. Raman microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis were used to characterize the particles. The mechanical properties, thermal stability, thermal conductivity, and dispersing status of the PMMA-based nanocomposites were also investigated. The results indicated that AP was grafted on the surface of GO via the amidation reaction, and the quantity of the grafted AP was approximately 20 wt% that of GO-AP. With the addition of GO-AP, the three-point bending strength of GO-AP/PMMA increased to approximately 58 MPa, and the dispersion of the particles was also enhanced. GO wrapped by AP could not form thermal conducting networks at the percolation thresholds. The increasing amount of AP prevented the formation of thermal conduction network and decreased the thermal conductivity of the composites. The thermal stability of the composites was affected by three main reasons, and the total effect of the three reasons on thermal stability illustrated a negative trend.

Collagen-Calcium Phosphate Hybrids for Bone Grafts: A Novel Route Leading to High Initial Strengths

2006 ◽  
Vol 309-311 ◽  
pp. 1185-1190 ◽  
Author(s):  
Xu Dong Li ◽  
Xiao Min Wang ◽  
Xiao Yan Lin ◽  
Jian Ming Jiang ◽  
Xing Dong Zhang
Keyword(s):  
Calcium Phosphate ◽  
Bending Strength ◽  
Three Dimensional ◽  
Bone Grafts ◽  
X Ray Diffraction ◽  
Three Point Bending ◽  
Dimensional Network ◽  
Efficient Route ◽  
Mechanical Strengths

An organic/inorganic composite hydrogel route was used to prepare collagen-calcium phosphate hybrids with high mechanical strengths, via in-situ mineral synthesis during collagen fibrillogenesis followed by dehydration. An array of characterization techniques including X-ray diffraction and Fourier transform infrared spectroscopy analyses confirmed that the final products are analogous to natural bone. A three-point bending strength of 70 MPa, much higher than the values reported in the literature, was recorded in the present case, due to the three dimensional network structure achieved between inorganic and organic phases. This innovative method provides an efficient route to produce bone grafts with the desirable mechanical properties which are dependent upon the actual inorganic/organic ratio and water content.

Mechanical properties of nanocrystalline copper produced by solution-phase synthesis

1996 ◽  
Vol 11 (2) ◽  
pp. 439-448 ◽  
Author(s):  
R. Suryanarayanan ◽  
Claire A. Frey ◽  
Shankar M. L. Sastry ◽  
Benjamin E. Waller ◽  
Susan E. Bates ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solution Phase ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
Nanocrystalline Copper ◽  
X Ray ◽  
Three Point Bending ◽  
Solution Phase Synthesis ◽  
Unique Method

Nanocrystalline copper powder was produced by a NaBH4 reduction of CuCl in a simple solution phase room temperature reaction. Uniaxial hot pressing in a closed tungsten die was used to compact powder into dense specimens. Samples were analyzed by x-ray diffraction, precision densitometry, electron microscopy, energy dispersive x-ray analysis, and selected area diffraction. Mechanical properties of the consolidated samples were determined by microhardness measurements, three-point bending of rectangular specimens, and compression tests. Yield strength measured for nanocrystalline Cu in the present work was over two times that reported in literature for Cu with comparable grain size and over five times that of conventional Cu. Restricted grain growth observed in the hot-pressed samples and improved mechanical properties are attributed to the presence of boron. A unique method of obtaining homogeneous in situ nanosized reinforcements to strengthen the grain boundaries in nanocrystalline materials is identified.

MECHANICAL AND THERMAL PROPERTIES OF MONTMORILLONITE-EPOXY NANOCOMPOSITE

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3247-3253 ◽  
Author(s):  
B. T. MAROUF ◽  
R. BAGHERI ◽  
R. A. PEARSON
Keyword(s):  
Thermal Properties ◽  
In Situ Polymerization ◽  
Mechanical And Thermal Properties ◽  
Toughening Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Epoxy Nanocomposite ◽  
Transmission Electron ◽  
Stiffening Effect

In this investigation, the mechanical and thermal properties of the montmorillonite-epoxy nanocomposites were studied. The epoxy compounds were prepared by in situ polymerization and the intercalation dispersion were obtained as evidenced using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results reveal remarkable stiffening effect and slight toughening effect of the MMT in the epoxy resin and an insight about the crack tip and notch tip toughening mechanism. According to the DMA, the glass transition temperature increases as increasing the MMT content.

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