Formation of the structure of powder-metallurgy coatings obtained by the impact wave method

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.

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Characterization of impinging jet sprays of gelled propellants loaded with nanoparticles in the impact wave regime

Fuel ◽

10.1016/j.fuel.2018.04.138 ◽

2018 ◽

Vol 228 ◽

pp. 10-22 ◽

Cited By ~ 3

Author(s):

Swarup Y. Jejurkar ◽

Geetanjali Yadav ◽

D.P. Mishra

Keyword(s):

Impinging Jet ◽

Wave Regime ◽

Impact Wave ◽

Gelled Propellants ◽

The Impact

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The effect of milling time on the alumina phase transformation in the AMCs powder metallurgy reinforced by silica-sand-tailings

EUREKA Physics and Engineering ◽

10.21303/2461-4262.2022.001906 ◽

2022 ◽

pp. 103-117

Author(s):

Sukanto ◽

Wahyono Suprapto ◽

Rudy Soenoko ◽

Yudy Surya Irawan

Keyword(s):

Particle Size ◽

Phase Transformation ◽

Powder Metallurgy ◽

Mechanical Alloying ◽

Milling Time ◽

Sintering Temperature ◽

Silica Sand ◽

Second Phase ◽

The Matrix ◽

The Impact

This study aims to determine the effect of milling time and sintering temperature parameters on the alumina transformation phase in the manufacture of Aluminium Matrix Composites (AMCs) reinforced by 20 % silica sand tailings using powder metallurgy technology. The matrix and fillers use waste to make the composites more efficient, clean the environment, and increase waste utilization. The milling time applied to the Mechanical Alloying (MA) process was 0.5, 6, 24, 48, and 96 hours, with a ball parameter ratio of 15:1 and a rotation of 93 rpm. Furthermore, hot compaction was carried out using a 100 MPa two-way hydraulic compression machine at a temperature of 300 °C for 20 minutes. The temperature variables of the sintering parameter process were 550, 600 to 650 °C, with a holding time of 10 minutes. Characterization of materials carried out included testing particle size, porosity, X-Ray Diffraction (XRD), SEM-Image, and SEM-EDX. The particle measurement of mechanical alloying processed, using Particle Size Analyzer (PSA) instrument and based on XRD data using the Scherrer equation, showed a relatively similar trend, decreasing particle size occurs when milling time was increased 0.5 to 24 hours. However, when the milling time increases to 48 and 96 hours, the particle size tends to increase slightly, due to cold-weld and agglomeration when the Mechanical Alloying is processed. The impact is the occurrence of the matrix and filler particle pairs in the cold-weld state. So, the results of XRD and SEM-EDX characterization showed a second phase transformation to form alumina compounds at a relatively low sintering temperature of 600 °C after the mechanical alloying process was carried out with a milling time on least 24 hours

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

10.21203/rs.3.rs-402620/v1 ◽

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.

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Study on Hypervelocity Impact Characteristics of Ti/Al/Mg Density-Graded Materials

Metals ◽

10.3390/met10050697 ◽

2020 ◽

Vol 10 (5) ◽

pp. 697

Author(s):

Luping Long ◽

Yingbiao Peng ◽

Wei Zhou ◽

Wensheng Liu

Keyword(s):

Powder Metallurgy ◽

Diffusion Bonding ◽

Areal Density ◽

Damage Mechanism ◽

Hypervelocity Impact ◽

Graded Materials ◽

Impact Process ◽

Graded Material ◽

The Impact ◽

Interface Bonding Strength

An improved shielding structure of a bumper that constructed from Ti/Al/Mg density-graded materials was presented. Two types of Ti/Al/Mg density-graded materials with the same areal density were prepared by diffusion bonding and powder metallurgy, respectively. The characteristics of hypervelocity impact including penetration holes in the bumper, damage patterns on the rear wall and micrographs of the crater were investigated. The results show that damage mechanism of Ti/Al/Mg density-graded materials is closely related to the interface bonding strength and matrix strength. The penetration holes of Ti/Al/Mg density-graded material obtained by diffusion bonding exhibit typical ductile characteristics. The Ti/Al/Mg density-graded material prepared by powder metallurgy shows significant mechanical synergistic response under high strain compression and appears fragile characteristic. The shielding performance of Ti/Al/Mg bumper is increased by 20.4% compared with aluminum bumper. A theoretical analysis suggests that a Ti-Al-Mg bumper can fully break the projectile and greatly increase the entropy during the impact process. Larger projectile kinetic energy is converted into the internal energy during the impact process, thereby causing an obvious increase in shielding performance.

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Simulation and Analysis of Anti-Explosion Capability for Coal Mine Refuge Chamber

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.941-944.2547 ◽

2014 ◽

Vol 941-944 ◽

pp. 2547-2552

Author(s):

Yuan Yuan Zhou ◽

Jun Lin Wan ◽

Ya Wei Zhao ◽

Qin Jian Mao

Keyword(s):

Numerical Simulation ◽

Finite Element Analysis ◽

Maximum Stress ◽

Transient Dynamics ◽

Gas Explosion ◽

Experiment Research ◽

Element Analysis ◽

Impact Wave ◽

Simulation Calculation ◽

The Impact

Experiment research aiming at the anti-explosion capability of the refuge chamber is a complex work with high costs. By using finite element analysis, however, could avoid this issue and implement the simulation and analysis more effectively. Based on transient dynamics approach, numerical simulation calculation and analysis of the dynamic response of the refuge chamber under the impact caused by gas explosion are presented in this paper. The results indicate that, when the refuge cabin under specified explosion impact wave stress, the maximum stress of the cabin is 370.8MPa,which is under the ultimate strength, and the maximum impact wave deformation of the cabin is 9.43mm, which is under the maximum permissive deformation (20mm), therefore the rigidity and the strength of the cabin both meet the demands. The refuge chamber presented in this paper, which remain the integrity of the cabin and the safety of the structure under specified explosion impact, has good anti-explosion ability, and could implemmet the emergency risk avoiding effectively.

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The effect of the blocking of impact ocean waves by the crevasse-ridden ice shelf

10.5194/egusphere-egu2020-9665 ◽

2020 ◽

Author(s):

Yuri Konovalov

Keyword(s):

Band Gap ◽

Numerical Experiments ◽

Amplitude Spectrum ◽

Ocean Waves ◽

Band Gaps ◽

Elastic Model ◽

Ice Shelf ◽

Impact Wave ◽

Wide Range ◽

The Impact

The propagation of high-frequency elastic-flexural waves through an ice shelf was modeled by a full 3-D elastic model, which also takes into account sub-ice seawater flow. The sea water flow is described by the wave equation. Numerical experiments were undertaken both for an intact ice shelf free of crevasses, which has idealized rectangular geometry, and for a crevasse-ridden ice shelf. The crevasses were modeled as triangle/rectangular notches into the ice shelf. The obtained dispersion spectra (the dispersion curves describing the wavenumber/periodicity relation) are not continuous. The spectra reveal gaps that provide the transition from n-th mode to (n+1)-th mode. These gaps are observed both for an intact ice shelf free of crevasses and for a crevasse-ridden ice shelf. They are aligned with the minimums in the amplitude spectrum. That is the ice shelf essentially blocks the impact wave at this transition. However, the dispersion spectrum obtained for a crevasse-ridden ice shelf, has a qualitatively difference from that obtained for an intact ice shelf free of crevasses. Moreover, the dispersion spectrum obtained for a crevasse-ridden ice shelf reveals the band gap &#8211; the zone there no eigenmodes exist (Freed-Brown and others, 2012). The numerical experiments with the crevasse-ridden ice tongue that is 16 km in longitudinal extent, 0.8km width and 100m thick, were undertaken for a wide range of the periodicities of the incident wave: from 5 s to 250 s. The obtained dispersion spectra reveal two band gaps in this range: the first band gap at about 20 s and the second band gap at about 7 s for 1km spatial periodicity of the crevasses. The width of the band gap significantly increases when the crevasses depth increases too. Respectively, the amplitude spectra reveal significantly increasing area of periodicities/frequencies where the ice shelf blocks the impact wave.ReferencesFreed-Brown, J., Amundson, J., MacAyeal, D., & Zhang, W. (2012). Blocking a wave: Frequency band gaps in ice shelves with periodic crevasses. Annals of Glaciology, 53(60), 85-89. doi:10.3189/2012AoG60A120Konovalov, Y.V. (2019). Ice-shelf vibrations modeled by a full 3-D elastic model. Annals of Glaciology, 1-7. doi:10.1017/aog.2019.9

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