scholarly journals Effects of TiB2 Particles on the Microstructure Evolution and Mechanical Properties of B4C/TiB2 Ceramic Composite

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5227
Author(s):  
Haiyan Niu ◽  
Yu Zhu ◽  
Ning You ◽  
Yangwei Wang ◽  
Huanwu Cheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ceramic Composite ◽  
Average Particle Size ◽  
Interface Energy ◽  
Ceramic Composites ◽  
Average Particle ◽  
Residual Tensile Stress ◽  
Sintering Process ◽  
Coherent Interface ◽  
Tib2 Particles

B4C/TiB2 ceramic composites reinforced with three size scales (average particle size: 7 μm, 500 nm, and 50 nm) of TiB2 were prepared by using a pressureless sintering furnace at 2100 °C under Ar atmosphere for 60 min. The results demonstrated that during the sintering process, TiB2 located on the boundaries between different B4C grains could inhibit the grain growth which improved the mass transport mechanism and sintering driving force. A semi-coherent interface between B4C and SiC was found, which is supposed to help to reduce the interface energy and obtain good mechanical properties of the B4C/TiB2 ceramic composite. On sample cooling from sintering temperature to room temperature, the residual tensile stress fields formed at the TiB2 interfaces owning to the thermo-elastico properties mismatched, which might have contributed to increase the ability of the sample to resist crack propagation. The results showed that the relative density, Vickers hardness, and fracture toughness of the composite with 20 wt.% submicron and 10 wt.% nano-TiB2 were significantly improved, which were 98.6%, 30.2 GPa, and 5.47 MPa·m1/2, respectively.

Experimental Study on the Effects of Internal Erosion on the Physical and Mechanical Properties of Tailings Under Unsteady Seepage

2021 ◽  
Author(s):  
Rong Gui ◽  
Guicheng He
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Shear Strength ◽  
Average Particle Size ◽  
Physical And Mechanical Properties ◽  
Internal Erosion ◽  
Average Particle ◽  
Sand Column ◽  
Sedimentary Characteristics ◽  
Seepage Erosion

Abstract In this paper, the hydraulic sedimentary model was established to investigate the effects of dry beach slope on the sedimentary characteristics of tailings, and the sand column model was built to investigate the effects of seepage erosion on the physical and mechanical properties of sedimentary tailings under unsteady seepage.The results show that the slope of dry beach have a great effect on the sedimentary characteristics of tailings, the average particle size of tailings decreases along the slope of dry beach, and the larger the slope, the more obvious the stratification of the tailings. The migration of fine-grained tailings caused by seepage erosion increases the permeability of the tailings and reduces the shear strength of the tailings. After seepage erosion,the average particle size of 1#tailings sample, 2#tailings sample and 3#tailings sample increased by 6.4%, 12.0% and 2.4% respectively, the hydraulic conductivity of 1# tailings sample, 2# tailings sample and 3# tailings increased by 27.2%,17.9%, and 15.3% respectively after internal erosion, and the shear strength of 1#tailings sample, 2#tailings sample and 3#tailings sample tailings sample decreased by 20.9 %, 15.1% and 12.4% respectively.

Study on Mechanical Properties of AA6061/SiC/B4C Hybrid Nano Metal Matrix Composites

2021 ◽  
Vol 1034 ◽  
pp. 35-42
Author(s):  
Shubhajit Das ◽  
M. Chandrasekaran ◽  
Sutanu Samanta
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Matrix Material ◽  
Average Particle Size ◽  
Volume Ratio ◽  
Casting Process ◽  
Hybrid Nanocomposites ◽  
Average Particle ◽  
Matrix Composites ◽  
Structural Applications

The present work investigates the mechanical characterization of aluminium alloy (AA) 6061 based hybrid nanometal matrix composites (MMCs) fabricated using conventional stir casting process. Two compositions viz., AA6061+1.5 wt.% B4C+0.5 wt.% SiC (Hybrid A) and AA6061+1.5 wt.% B4C+1.5 wt.% SiC (Hybrid B) was prepared and its mechanical properties such as microhardness, tensile, compressive, flexural and impact strength were investigated to compare with unreinforced AA6061. SiC and B4C ceramic particles (purity 99.89%) of average particle size of 50 nm were used as reinforcements. Significant enhancement in microhardness of 30.2% and 31.02% for hybrid A and B are observed respectively. The ultimate tensile strength (UTS) increased by 10.72% and 16.55% for hybrid A and B respectively. Improved interaction because of the enhanced surface to volume ratio at the interface resulted in improvement of mechanical properties. Field emission scanning electron microscopy (FESEM) of the fractured surface shows brittle fracture because of the incorporation of the ceramic reinforcements in the matrix material. The developed AA6061/SiC/B­4C hybrid nanocomposites show improved mechanical properties for high-performance structural applications.

Mechanical properties and erosive behaviour of 10TiO2-Cr2O3 coated CA6NM turbine steel under accelerated conditions

2019 ◽  
Vol 16 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Khushdeep Goyal
Keyword(s):  
Mechanical Properties ◽  
Mass Loss ◽  
Average Particle Size ◽  
Average Particle ◽  
Slurry Erosion ◽  
Experimental Conditions ◽  
Content Type ◽  
Uncoated Steel ◽  
Erosion Test ◽  
Turbine Steel

Purpose This paper aims to evaluate the mechanical properties and slurry erosion behaviour of 10TiO2-Cr2O3 coated turbine steel. Design/methodology/approach Slurry erosion experiments were performed on the coated turbine steel specimens using slurry erosion test rig under accelerated conditions such as rotational speed, average particle size and slurry concentration. Surface roughness tester, Vickers microhardness tester and scanning electron microscope were used to analyse erosion mechanism. Findings Under all experimental conditions, 10TiO2-Cr2O3 coated steel showed better slurry erosion resistance in comparison with Al2O3 coated and uncoated steel specimens. Each experimental condition indicated a significant effect on the erosion rate of both coatings and uncoated steel. The surface analysis of uncoated eroded specimen revealed that plastic deformation, ploughing and deep craters formation were the reasons for mass loss, whereas microchipping, ploughing and microcutting were the reasons for mass loss of coated specimens. Originality/value The present investigation provides novel insight into the comparative slurry erosion performance of high velocity oxy fuel deposited 10TiO2-Cr2O3 and Cr2O3 coatings under various environmental conditions. To form modified powder, 10 Wt.% TiO2 was added to 90 Wt.% Cr2O3.

scholarly journals Properties of Vulcanized Polyisoprene Rubber Composites Filled with Opalized White Tuff and Precipitated Silica

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Suzana Samaržija-Jovanović ◽  
Vojislav Jovanović ◽  
Gordana Marković ◽  
Ivana Zeković ◽  
Milena Marinović-Cincović
Keyword(s):  
Mechanical Properties ◽  
Production Efficiency ◽  
Average Particle Size ◽  
Rubber Matrix ◽  
Average Particle ◽  
Cross Link ◽  
Rubber Composites ◽  
Precipitated Silica ◽  
Reinforcing Effects ◽  
Cure Characteristic

Opalized white tuff (OWT) with 40 μm average particle size and 39.3 m2/g specific surface area has been introduced into polyisoprene rubber (NR). Their reinforcing effects were evaluated by comparisons with those from precipitated silica (PSi). The cure characteristic, apparent activation energy of cross-link (Eac) and reversion (Ear), and mechanical properties of a variety of composites based on these rubbers were studied. This was done using vulcanization techniques, mechanical testing, and scanning electron microscopy (SEM). The results showed that OWT can greatly improve the vulcanizing process by shortening the time of optimum cure (tc90) and the scorch time (ts2) of cross-linked rubber composites, which improves production efficiency and operational security. The rubber composites filled with 50 phr of OWT were found to have good mechanical and elastomeric properties. The tensile strengths of the NR/OWT composites are close to those of NR/PSi composites, but the tear strength and modulus are not as good as the corresponding properties of those containing precipitated silica. Morphology results revealed that the OWT is poorly dispersed in the rubber matrix. According to that, the lower interactions between OWT and polyisoprene rubber macromolecules are obtained, but similar mechanical properties of NR/OWT (100/50) rubber composites compared with NR/PSi (100/50) rubber composites are resulted.

Fabrication of A356-based rolled composites reinforced by Ni–P-coated bimodal ceramic particles

2016 ◽  
Vol 232 (10) ◽  
pp. 803-815 ◽  
Author(s):  
R Kheirifard ◽  
N Beigi Khosroshahi ◽  
R Azari Khosroshahi ◽  
R Taherzadeh Mousavian ◽  
D Brabazon
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Average Particle Size ◽  
Microstructural Characterization ◽  
Rolling Process ◽  
Stir Casting ◽  
Ceramic Particle ◽  
Average Particle ◽  
Ceramic Particles ◽  
Sic Particles

Three arrangements of reinforced A356-based composites were fabricated. Samples with 3 wt% Al2O3 (average particle size: 170 µm), 3 wt% SiC (average particle size: 15 µm), and 3 wt% of mixed Al2O3–SiC powders (each reinforcement 1.5 wt%) were fabricated. The novel fabrication process of two-step stir casting followed by rolling was utilized. Analysis of the effect of using bimodal-sized ceramic particles and process parameters on the microstructure and mechanical properties of the composites was examined. Electroless deposition of nickel was used to improve the wettability of the ceramic reinforcements by the molten metal. From microstructural characterization, it was found that fine SiC particles were agglomerated, including when coated with Ni–P. It was also revealed that the rolling process broke the fine silicon platelets within the A356 matrix, which were mostly observed around the Al2O3 particles. The processed microstructure of the composite was altered in comparison to conventionally cast A356 MMC by translocation of the fractured silicon particles, by improving the distribution of fine SiC particles, and by elimination of porosities remaining after casting. A good bonding quality at matrix–ceramic interface was formed during casting and no significant improvement was found in this regard after the rolling process. The mechanical properties of the composites tested showed that the samples, which contained the bimodal ceramic particle distribution of coarse Al2O3 and fine SiC particles produced the highest levels of composite strength and hardness.

scholarly journals 3D Online Submicron Scale Observation of Mixed Metal Powder's Microstructure Evolution in High Temperature and Microwave Compound Fields

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Dan Kang ◽  
Feng Xu ◽  
Xiao-fang Hu ◽  
Bo Dong ◽  
Yu Xiao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
High Temperature ◽  
Microstructure Evolution ◽  
Diffusion Mechanism ◽  
Average Particle Size ◽  
Average Particle ◽  
Reconstruction Method ◽  
Neck Size ◽  
Submicron Scale

In order to study the influence on the mechanical properties caused by microstructure evolution of metal powder in extreme environment, 3D real-time observation of the microstructure evolution of Al-Ti mixed powder in high temperature and microwave compound fields was realized by using synchrotron radiation computerized topography (SR-CT) technique; the spatial resolution was enhanced to 0.37 μm/pixel through the designed equipment and the introduction of excellent reconstruction method for the first time. The process of microstructure evolution during sintering was clearly distinguished from 2D and 3D reconstructed images. Typical sintering parameters such as sintering neck size, porosity, and particle size of the sample were presented for quantitative analysis of the influence on the mechanical properties and the sintering kinetics during microwave sintering. The neck size-time curve was obtained and the neck growth exponent was 7.3, which indicated that surface diffusion was the main diffusion mechanism; the reason was the eddy current loss induced by the external microwave fields providing an additional driving force for mass diffusion on the particle surface. From the reconstructed images and the curve of porosity and average particle size versus temperature, it was believed that the presence of liquid phase aluminum accelerated the densification and particle growth.

scholarly journals Experimental study on mechanical properties of steel - sand interface

2020 ◽  
Vol 143 ◽  
pp. 01030
Author(s):  
Zhaoxiao Fang ◽  
Weijiang Wang ◽  
Zhaoli Fang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Friction Coefficient ◽  
Average Particle Size ◽  
Average Particle ◽  
Shear Tests ◽  
Axial Pressure ◽  
Interface Shear ◽  
Interface Friction ◽  
Sand Particles

The interface between steel and sand can be regard as a steel-sand system, and its mechanical properties have an important role in many geotechnical applications. The mechanical properties of various steel-sand interfaces classified by sand mean particle size D50 were investigated through interface shear tests. The results show that for a given steel-sand interface, the peak strength of the interface increase with increasing axial pressure. As the D50 value increases, the cohesions for steel-sand interfaces decrease, while the friction angles of the interfaces first increase and then decrease. In the process of shearing, the shrinkage of steel-sand interface occurs, mainly due to the broken of sand particles. The decrease in interface friction coefficients due to an increase in axial pressure was observed. Particle size distribution has a significant effect on the interface friction coefficient of steel-sand interface. When the average particle size D50 changes from 0.1 mm to 0.47 mm, the friction coefficient of steel-sand interface increases by 134%-161%.

High Temperature Deformation Behavior and Microstructure Change in Nano Grain Composites

2007 ◽  
Vol 539-543 ◽  
pp. 745-750
Author(s):  
Naoki Miyano ◽  
Yusuke Kumagai ◽  
Masayoshi Yoshimoto ◽  
Shigeo Tanaka ◽  
Kazuo Isonishi ◽  
...  
Keyword(s):  
Average Particle Size ◽  
Xrd Analysis ◽  
Ceramic Composites ◽  
Low Flow ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Average Particle ◽  
Compression Tests ◽  
Plasma Sintering ◽  
Deformation Behaviors

One of the authors proposed a non-equilibrium powder metallurgy process, which enables the fabrication of a near net-shape product using TiC and TiN/Silicide ceramic composites. The PM process in combination with mechanical alloying (MA) and Spark Plasma Sintering (SPS) are applied to produce nano-grain composite, TiC/Ti5Si3. Powders of elements Ti and SiC whose composition is Ti-20 mass%SiC are blended for MA. After the alloying, the MA powder whose average particle size is 20~30 μm, has amorphous-like structures, and then the MA powder is compacted by SPS. Results of compression-tests indicate the occurrence of unusual hightemperature deformation behaviors such as low flow stress at the lower deformation temperature or at the high initial strain rates were observed in the SPS compacts. TEM observations of the deformed compacts after the compression-tests indicate the microstructure has no-strain equiaxial - grains and clear boundaries. This serves as proof of a superplasticity deformation. In addtion, the results of the XRD analysis of the compressed-compacts show that new phases are formed during the compression-test. Therefore, the above deformation is attributed to a "pseudo" superplasticity in which the phase transition of metastable microstructure occurs during the deformation.

The Effects of Cr2O3 Addition on Fracture Toughness and Phases of ZTA Ceramic Composite

2012 ◽  
Vol 620 ◽  
pp. 35-39 ◽  
Author(s):  
Ahmad Zahirani Ahmad Azhar ◽  
Nik Akmar Rejab ◽  
Mohamad Hasmaliza ◽  
Mani Maran Ratnam ◽  
Zainal Arifin Ahmad
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Vickers Hardness ◽  
Ceramic Composite ◽  
Weight Percent ◽  
Ceramic Composites ◽  
Oxide System ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Mechanical And Physical Properties

Fracture toughness and phases of ceramic composites produced from alumina, yttria stabilized zirconia and chromia oxide system was investigated. The Cr2O3weight percent was varied from 0 wt% to 1.0 wt%. Each batch of composition was mixed, uniaxially pressed 13mm diameter and sintered at 1600 C for 4 h in pressureless conditions. Studies on on their mechanical and physical properties such as Vickers hardness and fracture toughness were carried out. Results show that an addition of 0.6 wt% of Cr2O3produces the best mechanical properties. Results of the highest fracture toughness is 4.73 MPa.m1/2,

scholarly journals Advancement in Microstructural, Optical, and Mechanical Properties of PVA (Mowiol 10-98) Doped by ZnO Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
N. B. Rithin Kumar ◽  
Vincent Crasta ◽  
B. M. Praveen
Keyword(s):  
Mechanical Properties ◽  
Zinc Oxide ◽  
Zno Nanoparticles ◽  
Main Chain ◽  
Average Particle Size ◽  
Testing Machine ◽  
Average Particle ◽  
Zno Nanoparticle ◽  
X Ray ◽  
Xrd Studies

The current paper explores the preparation of PVA nanocomposites by doping with zinc oxide (ZnO) nanoparticles using the method of coagulation and solvent casting technique. The dopant zinc oxide nanoparticle is prepared by simple precipitation method and is confirmed by the X-ray diffraction (XRD) studies. The XRD studies explore that the average particle size of the synthesized nanoparticles is 55 nm and show that the crystallinity factor of PVA nanocomposites is influenced by the interaction occurring between the PVA main chain and the ZnO nanoparticle. The FTIR spectroscopy suggests that the formulation of complexes occurring between the dopants and the PVA main chain is due to inter or intra molecular hydrogen bonding. UV-vis spectra explore the dramatic decrease in the optical energy gap of nanoparticles doped polymer composites and the variations of Urbach energy (Eu) related to crystallinity for various dopant concentrations. The mechanical properties of the PVA nanocomposites were explored using universal testing machine (UTM) that reflects that, for x=15% doping concentration, there is an increase in the tensile strength, stiffness, and Young’s modulus, whereas, for x=7.5% concentration, the percentage total elongation at fracture is found to be the maximum. The morphological behavior and homogenous nanoparticle distribution in the composites were examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX).

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