Increase In Relative Density Research Articles

Consolidation and properties of tungsten by spark plasma sintering and hot isostatic pressing

The fabrication of dense tungsten was attempted with the combination process of presintering by spark plasma sintering and final hot isostatic pressing. The specimens fabricated by spark plasma sintering (1500–1600 °C) of commercial powder exhibited a relative density above 90.4%. In the case of the post hot isostatic pressing at 1650 °C for 2 h, improved relative density in the range of 96.4% to 97.2% was obtained. X-ray diffractometry and X-ray photoelectron spectroscopy analysis indicated that the sintered specimen was composed mainly of tungsten, and the trace amounts of metallic tungsten are bound with oxygen due to the surface oxidation. Strength measurement was conducted by biaxial bending test using a piston-on-three balls. Maximum flexural strength of 761 MPa were obtained for tungsten consolidated by a combined process of spark plasma sintering and hot isostatic pressing. The strength increase is explained by the increase in relative density rather than the effect of particle size.

Experimental Study on Stiffness Degradation and Liquefaction Characteristics of Marine Sand in the East Nan-Ao Area in Guangdong Province, China

Offshore wind power, as an efficient renewable energy source, is being vigorously developed nowadays. However, the liquefaction of marine sand due to earthquakes brings potential safety hazards to the wind turbine structures. In this study, a series of resonant column and undrained cyclic triaxial tests were carried out to investigate the stiffness degradation and liquefaction characteristics of marine sand in the offshore wind farm at the East Nan-ao area in Guangdong Province (China). Results show that the confining pressure increases the shear modulus of sand and restrains the nonlinearity of modulus. The liquefaction resistance of soils significantly increases with the increase of relative density. The effect of particle size on the liquefaction resistance is related to the cyclic shear stress ratio. The additional pressure induced by the presence of the wind turbine structure enlarges the energy required for shallow soil liquefaction. Besides, a model for predicting shear modulus and another modified model based on Seed’s pore pressure development model have been established, which can efficiently fit the dynamic shear modulus and the generation of excess pore water pressures in the tests, respectively.

Promoting core/surface homogeneity during flash sintering of 3YSZ ceramic by current path management: experimental and modelling studies

During flash sintering (FS) of ceramics, the heat loss by surface radiation is the main cause of temperature gradient between core and surface, which induces inhomogeneity in microstructure. To solve this problem, the judicious designing of sample geometry and electrodes configuration is proposed. Experimental and simulation results show that the application of dogbone shape, forked electrodes, and lower cross-section aspect ratio effectively shifts the current path in 3YSZ samples from core to near-surface during FS, compared to bar-shape samples with a single electrode at each end. Consequently, the temperature distribution becomes more uniform throughout the 3YSZ sample, resulting in increase in relative density from 92.7 % to 99.7 % and improved core/surface homogeneity in microstructure. These optimizations enable 3YSZ ceramics to obtain significant increase in flexural strength from 1203 ± 17 MPa to 1501 ± 15 MPa. A multiphysics model is implemented and compared with experimental results, which reveals the underlying mechanisms of improved sample homogeneity.

3D printed self-similar AlSi10Mg alloy hierarchical honeycomb architectures under in-plane large deformation

Self-similar hierarchical honeycombs with complicated cellular topologies are promising cores for lightweight sandwich structures ascribed to superior structural efficiency in terms of mitigating damage. In this paper, the in-plane compressive characteristics of AlSi10Mg alloy hierarchical honeycombs, fabricated using Selective Laser Melting (SLM) methodology, under large deformation are reported. The results suggest that higher hierarchies enhance the elastic modulus of honeycombs significantly, whereas the compressive strength is improved negligibly. There is a failure mechanism transition from cell wall bending dominated to cell wall fracture dominated with the increase of relative density and hierarchical order, and the failure mechanisms are related to the wall thickness with critical value of 0.345 mm. It is concluded that the in-plane failure of hierarchical honeycombs is dominated by the bending, axial compression and shear deformation of original unit cell walls. Besides, the parent material without heat treatment contributes to more excellent mechanical properties of hierarchical honeycombs owing to higher tensile strength and elastic modulus. This work enables to facilitate the structural design and optimization of high-performance hierarchical honeycomb metamaterials with desired properties and functions.

Diagnostic of Structural Changes in Ferromagnetic Powders during Milling in Beater Mill

Problem of obtaining fine powders of strontium hexa-ferrite is actual because of its wide applications. The paper provides the results of studies of particle size distribution and structural characteristic changes of strontium hexa-ferrite powder (SrFe12O19) during milling in impact mill and after its consequent annealing. Mechanical processing of coarse particulate system was carried out in the mill for 120 minutes without electromagnetic effect and with creation of magneto fluidized bed, formed by perpendicular constant and alternating magnetic field with induction gradient of 210 mT/m, providing reciprocating motion of particles and aggregates with sizes of 3 – 4 mm. It was shown that milling of coarse strontium hexa-ferrite with average particle size 1558.5 μm and the most possible size 1500 μm in magneto fluidized bed allowed to intensify milling process and to provide a significant increase of powder particle sizes uniformity. It was found out, that milling in magneto fluidized bed leads to a great decrease of coherent scattering regions sizes and an increase of lattice micro-deformations and relative dislocation density. Consequent annealing of the powder for 2 hours at 850°C refined structural characteristics significantly. The carried out research allows to choose the optimal milling duration for solution of practical problems of powder metallurgy.

Sinterability of Calcium Phosphate Through Rapid Sintering

Development of dense nanostructured hydroxyapatite (HA) with the major concern to enhance densification while limiting its grain growth has received great demand. This is due to inherent brittleness and lower mechanical strength of HA ceramic. A promising way to obtain this could be a fabrication of nanostructured HA materials through rapid sintering process. In this work, eggshell derived hydroxyapatite powder has been prepared via solid state route and its sinterability was investigated through microwave sintering (1000-1250 °C). The phase stability, microstructural evolution, relative density and hardness of the microwave sintered HA were reflected. The results indicate that the rapid sintering regime has been successfully employed with pure HA phase stability remained up to 1200°C and the relative density and hardness increase with increase in sintering temperature. On top of that, the result also showed good correlation of grain size and mechanical properties of HA and supported that microwave sintering did not promote extensive grain growth of HA.

Experimental Investigation on Seismic Compression of Sand Subjected to Multidirectional Cyclic Loads

The ground is simultaneously subjected to both horizontal and vertical motions during earthquakes; however, the majority of existing studies on seismic compression are still limited to the horizontal earthquake motions only. In this work, the objective is therefore to experimentally investigate the effects of multidirectional nature of load application on seismic compression of sand. Multiple series of hollow cylindrical torsional shear tests were conducted on dry sand specimens with different relative densities, where different scenarios of stress conditions induced by earthquakes were simulated by applying various combinations of vertical and horizontal cyclic loads. Test results revealed that coupling with horizontal motions, the vertical component of seismic loads would significantly contribute to the development of both shear and vertical strains in the sand specimen. The increment in vertical strain under coupled motions could be up to over 70% compared to its counterpart for the sand specimen under horizontal cyclic stress alone. Nevertheless, it is also interestingly found that the contribution of superimposed vertical motion alone to the growth of vertical strain is limited. Besides, the effect of relative density on the change of vertical strain is nonlinear, and the decreasing rate of vertical strain diminishes with the increase of relative density.

Experimental and Numerical Investigation for Vertical Stress Increments of Model Piled Raft Foundation in Sandy Soil

Piled raft foundations have become a prominent foundation system in recent years as they combine bearing capacities of piles and raft. For this reason, comprehensive analytical, numerical and experimental studies have been carried out for reliable and economic design of piled raft foundations. In this study, vertical stress increments were mainly investigated experimentally and numerically. In the experimental study, model composite (steel and concrete) piles with a diameter of 20 mm and lengths of 200 and 300 mm were used. The raft was made of steel plate with plan dimensions of 160 × 160 mm and a thickness of 6 mm. The pressure gauges were placed at 2.5D, 5D and 7.5D intervals axially below center of model piled raft in the sand. The tests were carried out at different relative densities with the model piled raft. After model tests, numerical analyses were carried out with the FEM-based software ABAQUS, and the results were compared with the experimental results. From the tests results, it is determined that the piled raft foundations transfer loads to the deep layers with the help of piles, and the vertical stress increment reduces downward from the end of the piles. However, it is seen that the increase in relative density decreases the vertical stress increments in sand for same load. Some design parameters are suggested for use in foundation engineering applications.

Influences of relative density and strain rate on the mechanical properties of Al-cenosphere-SWNTs hybrid foams

In the present study, single-walled carbon nanotubes (SWNTs) and cenosphere reinforced closed cell hybrid aluminium foams (HAFs) of varying relative densities were produced, and their compressive deformation behaviour at different strain rates have been examined. The addition of SWNTs leads to a significant increase in plateau stress, plastic collapse stress, and energy absorption. This may be due to higher dislocation density and finer inter-SWNT spacing. The Raman spectra of HAFs showed the uniform distribution of SWNTs in the cell wall region. However, the effect of quasi-static strain rates (10−3 to 10 s−1) on the compressive deformation response is marginal. While the influences of higher strain rate ranges (10−3 to 1500 s−1) are considerably higher than the quasi-static strain rate range. The strain rate sensitivity of these foams is much less than unity (~0.0088-0.0314), indicating the brittle nature of foam deformation. The plastic collapse, plateau stress, and energy absorption of HAFs increase significantly with an increase in relative density. Interestingly, it is observed that both plateau stress and energy absorption follow power-law relation with relative density, and densification strain follows a linear relation with relative density irrespective of strain rate and foam material. It is further noted that the strain rate sensitivity of HAFs increases marginally with relative density. The deformation mechanism of HAFs has been examined using the digital photographs captured during the uniaxial compression test and the SEM, TEM images of deformed specimens.

Enhanced aging and thermal shock performance of Mn1.95\u2212xCO0.21Ni0.84SrxO4 NTC ceramics

The Mn1.95−xCo0.21Ni0.84SrxO4 (MCNS) (0 ≼ x ≼ 0.15) based negative temperature coefficient (NTC) materials are prepared by co-precipitation method. The replacement of Mn by Sr plays a critical role in controlling the lattice parameter, relative density, microstructure, and electrical properties. The lattice parameter and relative density increase with the increase of Sr content. A small amount of Sr restrains the grain growth and increases the bulk density. Moreover, the room resistivity ρ25, material constant B25/50, activation energy Ea, and temperature coefficient α values of MCNS ceramics are influenced by the Sr content and ranged in 1535.0–2053.6 Ω·cm, 3654–3709 K, 0.3149–0.3197 eV, and (−4.173%)–(−4.111%), respectively. The X-ray photoelectron spectroscopy (XPS) results explain the transformation of MCNS ceramics from n- to p-type semiconductors. The conduction could arise from the hopping polaron between Mn3+/Mn4+ and Co2+/Co3+ in the octahedral sites. The impedance data analysis also discusses the conduction mechanism of the MCNS ceramic, whereas grain resistance dominates the whole resistance of the samples. Furthermore, the aging coefficient (ΔR/R) of MCNS ceramics is found to be < 0.2%, which indicates the stable distribution of cations in the spinel. Finally, the MCNS ceramics demonstrate excellent thermal durability with < 1.3% of resistance shift after100 thermal shock cycles.

Borehole enlargement rate as a measure of borehole instability in hydrate reservoir and its relationship with drilling mud density

Borehole collapse will pose a threat to the safety of equipment and personnel during drilling operation. In this paper, a finite element multi-field coupling model for investigating borehole collapse in hydrate reservoir was developed. In this model, fluid seepage, heat transfer, hydrate dissociation and borehole deformation are all considered. Based on which, effects of drilling fluid density on both of hydrate dissociation and borehole collapse are investigated. The investigation results show that disturbance of drilling fluid invasion to hydrate reservoir will lead to hydrate dissociation around wellbore, and dissociation range narrows obviously with the increase in drilling fluid density. When the relative fluid density is 0.98, natural gas hydrates in reservoir with a width of about 16.65 cm around wellbore dissociate completely. However, dissociation range of natural gas hydrate has decreased to 12.08 cm when the relative fluid density is 1.10. Moreover, hydrate dissociation around wellbore caused by drilling fluid invasion may lead to borehole collapse, and borehole collapse can be significantly restrained with the increase in relative fluid density. Borehole enlargement rate is 33.67% when the relative fluid density is 0.98, but nearly no collapse area displays around wellbore when the relative fluid density increases to 1.12. In addition, investigation herein can provide an idea for designing drilling fluid density in hydrate reservoir when different allowable borehole enlargement rate is considered. The minimum fluid density designed for avoiding disastrous borehole collapse increases nonlinearly when higher requirements for borehole stability are proposed.

Three‐dimensional lattice Boltzmann simulation of the permeability of soil‐rock mixtures and comparison with other prediction models

AbstractWith the discrete element method and the proposed virtual slicing technique for three‐dimensional discrete element model, random pore‐structural models of soil‐rock mixtures (SRMs) are constructed and voxelized. Then, the three‐dimensional lattice Boltzmann method (LBM) is introduced to simulate the seepage flow in SRMs on the pore scale and the influences of rock content, rock size, relative density on the simulated permeability of SRMs are comprehensively investigated. Finally, several theoretical models are introduced to predict the permeability of SRMs, and comparison is made between the results given by these prediction models and the numerical results obtained in this study. The results show that the permeability of SRMs presents a gradually increasing trend with the increase of rock content, and the rate of increase is also getting larger. When the other conditions remain unchanged, the permeability of SRMs decreases with the increase of relative density. When the rock content is lower than a threshold value, the permeability decreases as the rock size increases; however, this trend gets reversed when the rock content exceeds the threshold value. The permeability values of SRMs simulated with the LBM are lower in different levels than those calculated with the HS model, EMA model, and Zhou model, but most of them are very close to those predicted by the Daigle model.

Development, characterization and comparison of spark plasma-sintered Gr–Cu and Gr–Al composites reinforced with SiC and ZrB2 particles for thermal management

Graphite–copper (Gr–Cu) and graphite–aluminum (Gr–Al) composites are potential candidates for enhanced thermal management for different engineering applications. However, their applications are limited by inadequate thermal conductivity, high coefficient of thermal expansion (CTE) and low microhardness. In this study, SiC and ZrB2 were incorporated into Gr–Cu and Gr–Al powders, and then sintered in a spark plasma sintering (SPS) system to produce Gr–Cu + 8wt%SiC, Gr–Cu + 4wt%SiC + 4wt%ZrB2, Gr–Al + 8wt%SiC and Gr–Al + 4wt%SiC + 4wt%ZrB2 composites. After sintering, the physical, morphological, thermal, electrical and mechanical properties of the composites were evaluated. Results indicated 8.5% increase in relative density for reinforced Gr–Cu composites over the unreinforced Gr–Cu. The porosity of the reinforced Gr–Cu composites is 40.5% lower than that of the unreinforced and ~ 8% for reinforced Gr–Al. For all the sintered samples, Gr–Cu + 4wt%SiC + 4wt%ZrB2 sample has the highest hardness value of 44.5 HV0.1, highest peak intensity ratio of 80.19% and minimum CTE of 2.02 × 10–5/K. The huge increase in the microhardness and peak intensity ratio of Gr–Cu + 4wt%SiC + 4wt%ZrB2 is partially attributed to the formation of hard ZrC phase and three-bond system in ZrB2. This composite is recommended for thermal management of heat sinks and heat spreaders in electronics and pistons in automobiles.

Compaction behavior and densification mechanisms of Cu[sbnd]W composite powders

The deformation mechanism related to the initial relative density and uniformity of CuW composite powders under quasi-static compression was investigated by multi-particle finite element method. The results show that under the same pressure, the relative density of powder increases with the increase of initial relative density or the uniformity of composite powders. The densification processes can be divided into three stages, namely particle rearrangement, Cu particle deformation and W particle deformation. Pores are mainly filled by the rearrangement of particles and the deformation of Cu particles. The rearrangement and deformation of particles are quantitatively characterized by introducing the mean rotation degree and the mean equivalent strain of powders. It is found that smaller voids formed in the initial denser powder are easily filled by the deformation of adjacent particles during compaction. Strong force chains formed by the contact of W particles severely hinder the compression, resulting in large porosity.

The deformation characteristics of buried HDPE transfer lines in trenches under the effect of temperature

Today, the use of high-density polyethylene (HDPE) transfer lines is increasing day by day for drinking water, wastewater, sewerage networks, rainwater drainage lines, water transport structures, and natural energy sources, etc. In this study, flexible HDPE pipes were embedded in a trench to expose them to variable relative density and different thermal conditions so that the resulting deformation behavior could be investigated. Displacements and elastic strain values in the crown and spring line regions were measured. The main aim of this research was to determine the behavior of HDPE pipes under temperature effects within the framework of geotechnical principles to reflect real field conditions. As a result, pipes subject to vertical loading were tested under different relative density and thermal conditions. In the experiments carried out in a silica sandy trench, the deformations increased due to an increase in relative density. The maximum displacements and bending moment values were obtained at 50°C, which was the maximum thermal condition applied. An increase in temperature increased the deformation values due to the resulting decrease in the modulus of elasticity.

Shear strength behaviour of coral gravelly sand subjected to monotonic and cyclic loading

The paper presents an experimental study on the strength behaviour of a coral gravelly sand from Vietnam subjected to monotonic and cyclic loading. A series of direct shear tests were carried out to investigate the shear strength behaviour and the factors affecting the shear strength of the sand such as relative density, cyclic load, amplitude of the cyclic load and loading rate. The study results indicate that the shear strength parameters of the coral gravelly sand include not only internal friction angle but also apparent cohesion. These parameters vary with the relative density, cyclic load, the amplitude of the cyclic load and loading rate. The shear strength increases with the increase of the relative density. The shear strength increases after subjecting to cyclic loading. The amplitude of the cyclic load affects the shear strength of coral gravelly sand, the shear strength increases as the amplitude of the cyclic load increases. The loading rate has insignificantly effect on the shear strength of the coral gravelly sand.

Combustion in Ni–Al system with Cu additive (powder or rod) Experiment and mathematical model

Experimental studies were carried out with theoretical calculations of wave synthesis in the Ni–Al–Cu system were performed using the mathematical model developed. Approximate analytical formulas were obtained for synthesis performance evaluation. The inverse problem method was used to get kinetic constants that determine process dynamics based on the experimental data and analytical relationships. It is shown that the combustion front propagation velocity increases monotonically with an increase in the reaction sample relative density in the range of relative density values of 0.4 to 0.6. The depth of copper melt penetration from the center of the sample into the nickel-aluminum matrix depends on the relative density of the sample and copper wire diameter: higher densities and larger diameters lead to an increase in the liquid-phase impregnation area. The rate of nickel and aluminum powder frame wetting with copper melt is limited by the synthesis wave speed. Based on the experimental data and analytical ratios, we estimated the effective kinetic constants describing the high-temperature synthesis of the Ni + Al reaction mixture in the presence of copper additives. The thermal effect of the NiAl intermetallic formation reaction and the preexponential factor in the chemical transformation equation are calculated, the exponent value in the ratio for the mixture thermal conductivity is established; a constant determining the process of nickel-aluminum matrix impregnation with copper melt is found. The macroscopic approach used to analyze the NiAl intermetallic synthesis makes it possible to determine all the desired physicochemical characteristics and model parameters. The mathematical model is suitable for predictive estimates and experimental data analysis in the macroscopic approximation. Approximate analytical formulas are obtained for calculating the NiAl intermetallic synthesis characteristics. They allow for calculating the through channel characteristics and can be used in the design of NiAl products.

Crystal structure, Raman spectra, and microwave dielectric properties of high-Q Li2ZnTi3O8 systems with Nb2O5 addition

Li2ZnTi3O8(LZT)-xwt.%Nb2O5 (x = 0, 1, 2, 3, 4) microwave dielectric ceramics were synthesized by the conventional solid-phase sintering method. The effect of Nb2O5 addition on crystal structure, Raman spectra, and dielectric properties were studied. X-ray diffraction results indicated that the maximum crystallinity of LZT ceramics were obtained at 1075 °C, and that Nb5+ diffused into the LZT matrix completely to form a stable solid solution. XRD refinement results demonstrated that the substitution of Nb5+ for Ti4+ caused the cell volume to increase. The microscopic morphology of LZT-xwt.%Nb2O5 (x = 0, 1, 2, 3, 4) ceramics were further investigated by scanning electron microscopy, and results indicated that Nb2O5 could promote the grain growth and sintering of LZT ceramics. Extrinsic and intrinsic dielectric losses were studied through Raman and impedance spectroscopy. The highest value of quality factor × resonant frequency (Q × f) was attributed to the increase in relative density and reduced number of oxygen vacancies (VO••), as well as the decrease in damping behavior. Moreover, the dielectric constant (εr) showed the same trend as cell polarization and the temperature coefficient of resonant frequency (τf) was inversely proportional to cell volume. The LZT ceramics with 3 wt% Nb2O5 addition sintered at 1075 °C for 4 h exhibited the optimal microwave properties, i.e., εr = 26.52, Q × f = 66 304 GHz, and τf = - 14.2 ppm/°C.

Elucidation of Densification Experienced By LLZO Solid Electrolytes

In order to improve the energy density and minimize the safety concerns associated with the liquid electrolytes used in the present day lithium ion batteries, solid electrolytes are being actively considered for use in the next generation energy storage devices.[1] Among various ceramic based solid state electrolytes being investigated, Li7La3Zr2O12 (LLZO) with a garnet crystal structure demonstrates very high ionic conductivity and is extremely stable against lithium.[2] Hence, LLZO is being actively considered as the electrolyte for next generation lithium ion batteries. However, due to poor processing of these ceramics, they contain pores and voids.[3] These open spaces within the bulk not only decrease the effective conductivity of the electrolyte, but also provides open pathways for Li dendrites to propagate. Presence of pores within the ceramic structure can be estimated from the final relative density of the solid electrolyte. High temperature sintering induced densification of the LLZO particles are conducted to improve the relative density of the final solid electrolyte, and this process helps to minimize the void space within the structure.[3, 4] Sometime external pressures are applied to further improve the relative densities.[5] Even though several experimental studies have been conducted for constructing the LLZO solid electrolytes, very little effort has been devoted to actually understand the physical mechanisms that play major role during the densification process.In the present context, a computational methodology has been developed at the mesoscale level to understand the impact of surface and grain-boundary diffusion mechanisms on the overall grain ripening and densification experienced by the LLZO solid electrolytes during the sintering process conducted at elevated temperatures. During densification, the extent of increase in relative density depends on the activation energy associated with the diffusive mass transport processes. Here, the activation energy for LLZO will be estimated from direct comparison of relative densities obtained from the developed computational model and experimental observations.[6] Some strategies, in terms of particle sizes and size distributions, that can lead to improved relative densities within the LLZO solid electrolytes, will also be discussed in this presentation. References Zhang, Z., et al., New horizons for inorganic solid state ion conductors. Energy & Environmental Science, 2018. 11(8): p. 1945-1976. Ramakumar, S., et al., Lithium garnets: synthesis, structure, Li+ conductivity, Li+ dynamics and applications.Progress in Materials Science, 2017. 88: p. 325-411. Rangasamy, E., J. Wolfenstine, and J. Sakamoto, The role of Al and Li concentration on the formation of cubic garnet solid electrolyte of nominal composition Li7La3Zr2O12. Solid State Ionics, 2012. 206: p. 28-32. Sharafi, A., et al., Controlling and correlating the effect of grain size with the mechanical and electrochemical properties of Li7La3Zr2O12 solid-state electrolyte. Journal of Materials Chemistry A, 2017. 5(40): p. 21491-21504. Dzepina, B., D. Balint, and D. Dini, A phase field model of pressure-assisted sintering. Journal of the European Ceramic Society, 2019. 39(2-3): p. 173-182. Shin, R.-H., et al., Effect of Li3BO3 additive on densification and ion conductivity of garnet-type Li7La3Zr2O12 solid electrolytes of all-solid-state lithium-ion batteries. Journal of the Korean Ceramic Society, 2016. 53(6). Figure 1

Effect of compressive strain rate on the deformation behaviour of austenitic stainless steel foam produced by space holder technique

316L austenitic stainless steel foam (ASSF) with 55–81% porosities was made by P/M route using urea as space holder. The cold compacted at 500 MPa pressure and sintered at 1200 °C for 60 min. Microstructure, cell size, cell walls thickness and micro-hardness were evaluated. Twins boundaries are visible in cell wall regions. XRD, FESEM, and EDX analysis proved that no residue of space holder particles remained in the sintered foam samples. The compressive deformation behaviour of sintered foam samples are studied under three different strain rate (0.001, 0.01, and 0.1 s−1). The yield stress (σy), average plateaus stress (σpl), elastic modulus (Ef) and energy absorption (Eab) increases with increase in relative density (ρrd), and also increased with increasing strain rate. Densification strain decreased with increasing strain rate and follows linear relationship with ρrd. The yield stress, elastic modulus, and densification strain were compared with Gibson-Ashby's model and are found to be in closed agreement. The stain rate parameter (Σ) marginally decreases with increase in ρrd and follows linear relationship with ρrd.