Effect of Presence of Nano-Size Alumina Particles on the Properties of Elemental Magnesium

2005 ◽  
Vol 23 ◽  
pp. 171-174 ◽  
Author(s):  
X.L. Zhong ◽  
Manoj Gupta
Keyword(s):  
Powder Metallurgy ◽  
Uniform Distribution ◽  
Dimensional Stability ◽  
Microstructural Characterization ◽  
Alumina Content ◽  
Alumina Particles ◽  
Higher Temperature ◽  
Characterization Studies ◽  
Nano Size ◽  
Composite Samples

In present study, elemental magnesium was reinforced with nano-size alumina particles (50-nm). The composite samples were synthesized using the technique of powder metallurgy and the effect of extrusion temperature and sintering on the end properties was particularly investigated. The results of microstructural characterization studies confirmed the presence and reasonably uniform distribution of alumina particles. Results obtained from extruded unsintered samples revealed that the hardness and dimensional stability of magnesium increases with an increasing presence of alumina particles while the 0.2%YS, UTS and ductility deteriorated. Results further revealed that including sintering step and extruding at higher temperature lead to an increase in dimensional stability, hardness, 0.2%YS, UTS and ductility for an alumina content as low as one percent by weight.

scholarly journals Microstructural Characterization and Mechanical Behaviour of SiC and Kaoline Reinforced Aluminium Metal Matrix Composites Fabricated through Powder Metallurgy Technique

2021 ◽  
Author(s):  
venkatesh vavilada ◽  
Ashish B Deoghare
Keyword(s):  
Powder Metallurgy ◽  
Mechanical Behaviour ◽  
Hybrid Composite ◽  
Metal Matrix ◽  
Compaction Pressure ◽  
Maximum Yield ◽  
Microstructural Characterization ◽  
Powder Metallurgy Technique ◽  
The Impact ◽  
Composite Samples

Abstract In this study, the effect of naturally available and low-cost kaoline particles on the microstructural and mechanical behaviour of Al- SiC- Kaoline Hybrid metal matrix composite was investigated. Al-10% SiC- x% Kaoline (X = 0, 2, 4, 6, 8) composite samples were fabricated through powder metallurgy technique by applying a compaction pressure of 350 MPa. The fabricated composite samples were subjected to Density, Hardness, tensile and impact tests to study the mechanical behaviour of fabricated hybrid composite. The presence of SiC and Kaoline reinforcements was confirmed by using SEM and X-Ray Diffraction analysis. It was observed that the maximum ultimate tensile strength (U.T.S) and maximum Yield Strength (Y.S) of the hybrid composite were found to be 263 MPa and 202 MPa for Al-10%SiC-4%kaoline reinforcement. The formation of the intermetallic compound such as Al2Cu was observed in XRD and SEM analysis for Al-10% SiC-6 % kaoline and Al-10% SiC-8% of kaoline reinforcement which leads to decrease in the U.T.S and Y.S of fabricated specimens. The impact strength of Al-10%SiC-8% kaoline found to be decreased by 44.4% compared to unreinforced Aluminium due to the presence of harder SiC and Kaoline reinforcements particles. To study the fracture mechanism, Scanning Electron Microscopy study was carried on the fractured Tensile specimens which reveal that ductile fracture in unreinforced Al, Al-10% SiC, Al-10% SiC-2% Kaoline due to the formation of dimples and Brittle fracture was observed in Al-10% SiC-4% Kaoline, Al-10% SiC-6% Kaoline and Al-10% SiC-8% Kaoline due to the existence of cleavages and microcracks.

Gradient Nickel – Alumina Composite Coatings

2006 ◽  
Vol 530-531 ◽  
pp. 261-268 ◽  
Author(s):  
Clarice Terui Kunioshi ◽  
Olandir Vercino Correa ◽  
Lalgudi Venkataraman Ramanathan
Keyword(s):  
Powder Metallurgy ◽  
Metal Matrix ◽  
Composite Coatings ◽  
Microstructural Characterization ◽  
Process Conditions ◽  
Electrodeposition Process ◽  
Alumina Particles ◽  
Creep Fatigue ◽  
Alumina Composite ◽  
Alumina Composites

Particle reinforced metal matrix composite (MMC) coatings have been developed due to property combinations such as increased hardness, high creep/fatigue resistance as well as superior wear and oxidation resistance. MMC coatings can be produced by various techniques, which include powder metallurgy (plasma spray and HVOF processes), liquid metal processes and electrodeposition. This paper presents the development of the electrodeposition process to obtain nickel-alumina composites. The process conditions were optimized and based on these gradient nickel-alumina composites were prepared. Microstructural characterization and hardness determinations were carried out. The effect of process parameters on the amount and distribution of alumina particles as well as morphology of the deposits with and without alumina gradients are presented and discussed.

Development of Mg/Cu Nanocomposites Using Microwave Assisted Powder Metallurgy Technique

Materials ◽  
2005 ◽  
Author(s):  
W. L. E. Wong ◽  
M. Gupta
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Physical And Mechanical Properties ◽  
Microstructural Characterization ◽  
Radiant Heat ◽  
Powder Metallurgy Technique ◽  
Microwave Assisted ◽  
The Matrix ◽  
Rapid Sintering ◽  
Nano Size

In the present study, magnesium composites containing different amount of nano-size copper particulates were successfully synthesized using powder metallurgy technique coupled with a novel microwave assisted rapid sintering. Mg/Cu nanocomposites were sintered using a hybrid heating method consisting of microwaves and radiant heat from external susceptors. The sintered specimens were hot extruded and characterized in terms of microstructural, physical and mechanical properties. Microstructural characterization revealed minimal porosity and the presence of a continuous network of nano-size Cu particulates decorating the particle boundaries of the metal matrix. Mechanical characterization revealed that the addition of nano-size Cu particulates lead to an increase in hardness, 0.2% yield strength (YS) and ultimate tensile strength (UTS) of the matrix. An attempt is made in the present study to correlate the effect of increasing presence of nano-size Cu reinforcement on the microstructural, physical and mechanical properties of monolithic magnesium.

Development of Al-Mg Based Composites Containing Nanometric Alumina Using the Technique of Disintegrated Melt Deposition

2005 ◽  
Vol 23 ◽  
pp. 159-162 ◽  
Author(s):  
K.F. Ho ◽  
Manoj Gupta
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Dominant Role ◽  
Hot Extrusion ◽  
Microstructural Characterization ◽  
Magnesium Content ◽  
Characterization Studies ◽  
Mechanical Properties Characterization ◽  
Melt Deposition ◽  
Composite Samples

In this study, composites based on Al-Mg/Al2O3 formulation were fabricated using an innovative solidification route followed by hot extrusion. The studies clearly indicate an increase in retention of nanometric alumina with an increase in magnesium content. Microstructural characterization studies of the extruded composite samples displayed fairly uniform distribution of reinforcement phases and minimal porosity. Results of mechanical properties characterization showed that a cumulative increase in magnesium and nanometric alumina content led to an increase in elastic modulus, 0.2% YS and UTS while the ductility of the composite was adversely affected. A comparison between monolithic Al-3.8Mg and Al-3.4Mg/1.4Al2O3 revealed that the presence of nanometric alumina play a dominant role in realizing a significant increase in elastic modulus, 0.2%YS and UTS of the composites.

Analysis of tribological properties of graphite and aluminum composite materials prepared by powder metallurgy technique

2020 ◽  
Vol 10 (5) ◽  
pp. 663-670
Author(s):  
Zhigang Wang ◽  
Jun Li ◽  
Daquan Li
Keyword(s):  
Composite Materials ◽  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Tribological Properties ◽  
Utilization Rate ◽  
Powder Metallurgy Technique ◽  
Aluminum Composite ◽  
Powder Metallurgy Process ◽  
Metallurgy Process ◽  
Composite Samples

In order to make full use of the wear resistance and antifriction of the mixed reinforced particles, improve the performance and utilization rate of the composite material, and reduce its wear amount, in this study, graphite and aluminum composite materials with different graphite concentration were prepared by powder metallurgy process. On this basis, the influence of different graphite concentration on the friction coefficient and wear amount of composite samples and different load on the wear amount of composite materials were discussed and analyzed. The results show that with the increase of graphite content, the friction coefficient and wear amount of the composite will decrease correspondingly. When the load is less than 30 N, the wear curve of the sample changes steadily. When the load is more than 30 N, the wear will increase sharply. Therefore, the analysis of the tribological properties of the graphite and aluminum composites based on the powder metallurgy process plays an important role in improving the utilization rate of the composite and reducing its wear.

scholarly journals Alumina-Doped Zirconia Submicro-Particles: Synthesis, Thermal Stability, and Microstructural Characterization

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2856 ◽  
Author(s):  
Gregor Thomas Dahl ◽  
Sebastian Döring ◽  
Tobias Krekeler ◽  
Rolf Janssen ◽  
Martin Ritter ◽  
...  
Keyword(s):  
Grain Growth ◽  
Sol Gel ◽  
Microstructural Characterization ◽  
Alumina Content ◽  
Stabilizing Agents ◽  
Precise Control ◽  
Size And Shape ◽  
Elemental Analyses ◽  
Sol Gel Synthesis ◽  
And Control

Zirconia nanoceramics are interesting materials for numerous high-temperature applications. Because their beneficial properties are mainly governed by the crystal and microstructure, it is essential to understand and control these features. The use of co-stabilizing agents in the sol-gel synthesis of zirconia submicro-particles should provide an effective tool for adjusting the particles’ size and shape. Furthermore, alumina-doping is expected to enhance the particles’ size and shape persistence at high temperatures, similar to what is observed in corresponding bulk ceramics. Dispersed alumina should inhibit grain growth by forming diffusion barriers, additionally impeding the martensitic phase transformation in zirconia grains. Here, alumina-doped zirconia particles with sphere-like shape and average diameters of ∼ 300 n m were synthesized using a modified sol-gel route employing icosanoic acid and hydroxypropyl cellulose as stabilizing agents. The particles were annealed at temperatures between 800 and 1200 ∘ C and characterized by electron microscopy, elemental analysis, and X-ray diffraction. Complementary elemental analyses confirmed the precise control over the alumina content (0–50 mol%) in the final product. Annealed alumina-doped particles showed more pronounced shape persistence after annealing at 1000 ∘ C than undoped particles. Quantitative phase analyses revealed an increased stabilization of the tetragonal/cubic zirconia phase and a reduced grain growth with increasing alumina content. Elemental mapping indicated pronounced alumina segregation near the grain boundaries during annealing.

scholarly journals Effect of Moderate Temperature Thermal Modification Combined with Wax Impregnation on Wood Properties

2020 ◽  
Vol 10 (22) ◽  
pp. 8231
Author(s):  
Jing-Wen Zhang ◽  
Hong-Hai Liu ◽  
Lin Yang ◽  
Tian-Qi Han ◽  
Qin Yin
Keyword(s):  
Mechanical Strength ◽  
Dimensional Stability ◽  
Color Change ◽  
Strength Loss ◽  
Wood Properties ◽  
Thermal Modification ◽  
Moderate Temperature ◽  
Modulus Of Rupture ◽  
Internal Surfaces ◽  
Higher Temperature

Thermal modification (TM) improves the hydrophobicity, dimensional stability, and durability of wood, but TM commonly results in severe color change and mechanical strength loss as wood is treated at higher temperature. In this study, Pterocarpus macrocarpus Kurz wood was thermally modified at moderate temperature (150 °C) and higher temperature (200 °C), and subsequently TM wood at 150 °C was subjected to wax impregnation (WI), the effect of a combination of TM and WI on the hygroscopicity, dimensional stability, and mechanical properties, as well as the micro-structure of wood, were investigated and compared. The results showed that the mass loss of wood was slight at 150 °C TM, while it became severe at 200 °C TM conditions. TM conditions affected the amount of the subsequent wax impregnation; the equilibrium moisture content (EMC), water absorption ratio, and adsorption and absorption swelling of the 150 °C TM + WI group were lower than that of 200 °C TM, and presented the lowest value. Moderate temperature TM could improve the hydrophobicity and dimensional stability of wood, but WI played a key role in the improvement. TM decreased the modulus of rupture (MOR) of wood, while WI improved the MOR. TM increased the modulus of elasticity (MOE) of wood, but WI had little effect on MOE; Scanning electron microscope (SEM) observation showed that the wax was successfully impregnated into the wood interior, and presented an even distribution on the internal surfaces of wood cells; Fourier-transform infrared spectroscopy (FTIR) spectra verified the changes of –OH and C=O after TM and TM + WI, which contributed to decreasing hygroscopicity and improving the dimensional stability of the wood. Impregnated wax improved wood mechanical strength, but decreased the lightness, and deepened the color of wood. The combination of thermal modification at moderate temperature with subsequent wax impregnation is a practical approach for improving wood properties.

Heat Treatment and Oxidation Characteristics of Nb-20Mo-15Si-5B-20(Cr,Ti) Alloys from 700 to 1400°C

2010 ◽  
Vol 638-642 ◽  
pp. 2351-2356 ◽  
Author(s):  
Sylvia Natividad ◽  
Arianna Acosta ◽  
Krista Amato ◽  
Julieta Ventura ◽  
Benedict Protillo ◽  
...  
Keyword(s):  
Unit Area ◽  
Annealing Treatment ◽  
Microstructural Characterization ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Ti Alloy ◽  
X Ray ◽  
Ti Alloys ◽  
Higher Temperature ◽  
Oxidation In Air

Nb-20Mo-15Si-5B-20(Cr,Ti) alloys have been subjected to annealing treatment for 2 hours in a range of temperatures from 700 to 1400oC and quenched in water to perform the microstructural characterization for these two new alloys. As cast structure consists of a solid solution phase, , and silicides (Nb5Si3) in both alloys but Cr alloy also contains NbCr2 and Nb3Si phases. Heating to higher temperature introduces Ti silicides in the microstructure for Ti alloy. The oxidation in air has been conducted on these alloys in the same temperature range for 24 hours. Weight gain per unit area as a function of temperature provides the oxidation curves while characterization techniques using SEM, EDS on SEM, x-ray mapping, and XRD has yielded the analyses of the oxide scale. The scale consists of various oxides of Nb, Mo, Cr, Si, and Ti. Cr alloy appears to offer higher oxidation resistance in the selected range of oxidation temperatures.

EVIDENCE OF THICKNESS-DEPENDENT STABILITY OF NANOMETER RANGE W/Ni MULTILAYERS AGAINST SWIFT HEAVY ION IRRADIATION

2011 ◽  
Vol 10 (01n02) ◽  
pp. 99-103
Author(s):  
SHARMISTHA BAGCHI ◽  
N. P. LALLA ◽  
SHAHID ANWAR
Keyword(s):  
Electronic Excitation ◽  
Ion Irradiation ◽  
Microstructural Characterization ◽  
Heavy Ion ◽  
Bilayer Thickness ◽  
Cross Sectional ◽  
Swift Heavy Ion Irradiation ◽  
Heavy Ion Irradiation ◽  
Swift Heavy Ion ◽  
Characterization Studies

We report microstructural characterization studies, including cross-sectional TEM, carried out on pristine and swift heavy ion irradiated W / Ni multilayers with different bilayer thicknesses. Our results very clearly show a strong thickness dependence of the SHI effect; thinner Ni -layers get severely affected while the thicker ones remain intact. This has been confirmed using a multilayer having composite bilayer thickness. This result appears to indicate toward the possible electron conferment and its implication on the dissipation of electronic excitation in metals.

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