Some features of powder densification in various stages of pressing

Radomysel'skii, I. D.; Shcherban, N. I.

doi:10.1007/bf00793458

Cited by 7 publications

(7 citation statements)

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“…According to the authors, the parameters k and n are very close to the reference values for the powder material [55]. Therefore, in equation ( 40), the parameters k and n are known in advance, and the parameters ΘM and ξ determined by fitting the curve according to equation (40) to the experimental compaction curve of a particular powder. In the authors' opinion, the advantage of equation ( 40) is the use of previously known parameters k and n with a clear physical meaning.…”

Section: Modern Work Describing the Process Of Powder Compaction In A...mentioning

confidence: 91%

“…In the above equations, PCP is conceded to be a monotonous process without any indication that, in reality, it proceeds in several stages with their own mechanisms of powder densification. Most experts agree on the existence of three stages of PCP, although according to some authors, there are 4 stages [40,41]. The three stages are characterized as follows.…”

Section: Mate-rialmentioning

confidence: 99%

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New Die-Compaction Equations for Powders as a Result of Known Equations’ Correction. Part 1. Review and Analysis of Various Die-Compaction Equations

Laptiev

2023

Preprint

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The well-known equations for the process of powder compaction (PCP) in a rigid die published over the period from the beginning of the last century to the present are considered. Most of the considered equations are converted into the dependence of the densification pressure on the relative density. The equations were analyzed and their ability to describe PCP was assessed by determining the coefficient of determination when approximating experimental data on the compaction of various powders. It is shown that most of the equations contain two constants, the values of which are determined by fitting the mathematical dependence to the experimental curve. Such equations are able to describe PCP with high accuracy in the case of compaction of powders up to a relative density of 0.9-0.95. It is also shown that different equations can describe PCP in the range of density change from the initial to 0.9 with the same and sufficiently high accuracy, but when the process of compaction is extrapolated to higher values of density, the curves diverge. This indicates the importance of equations that can unambiguously describe PCP to a relative density equal to or close to 1.0. For an adequate description of PCP to a relative density greater than 0.95, equations containing three or four constants have proven themselves well.

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Section: Modern Work Describing the Process Of Powder Compaction In A...mentioning

confidence: 91%

Section: Mate-rialmentioning

confidence: 99%

New Die-Compaction Equations for Powders as a Result of Known Equations’ Correction. Part 1. Review and Analysis of Various Die-Compaction Equations

Laptiev

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…In the above equations, PCP is conceded to be a monotonous process without any indication that, in reality, it proceeds in several stages with their own mechanisms of powder densification. Most experts agree on the existence of three stages of PCP, although according to some authors, there are 4 stages [42,43]. The three stages are characterized as follows.…”

Section: Accuracy Assessment Of Pcp Description Using Equations Obtai...mentioning

confidence: 99%

“…Powders 2024, 3 132 density of the material instead of the relative density. If we transform Equation (42) into the dependence of pressure on relative density, then we obtain power law:…”

Section: Parametermentioning

confidence: 99%

“…where ρ 0 and ρ are relative initial and current densities, respectively, A ′ = 1/A (1/B) and B ′ = 1/B are constant parameters obtained from the experiment. Note that using of the power law to describe PCP is not a new solution (see Equation (3)), but Equation (42) takes into account the real fact that at a density equal to the initial density ρ 0 , the compaction pressure is zero. However, in the long-known equation ( 3), it is easy to take into account this fact if instead of the current relative density ρ we substitute the expression (ρ − ρ 0 )/(1 − ρ 0 ), that allows taking into account not only the initial density but also the entire range of density changes from ρ 0 to ρ = 1.Then Equation (3) will acquire the form:…”

Section: Parametermentioning

confidence: 99%

See 1 more Smart Citation

New Die-Compaction Equations for Powders as a Result of Known Equations Correction: Part 1–Review and Analysis of Various Die-Compaction Equations

Laptiev

2024

Powders

View full text Add to dashboard Cite

The well-known equations for the powder compaction process (PCP) in a rigid die published from the beginning of the last century until today were considered in this review. Most of the considered equations are converted into the dependences of densification pressure on the powder’s relative density. The equations were analyzed and their ability to describe PCP was assessed by defining the coefficient of determination when approximating experimental data on the compaction of various powders. It was shown that most of the equations contain two constants the values of which are determined by fitting the mathematical dependence to the experimental curve. Such equations are able to describe PCP with high accuracy for the compaction of powders up to a relative density of 0.9–0.95. It was also shown that different equations can describe PCP in the density range from the initial density to 0.9 with the same high accuracy, but when the process of compaction is extrapolated to higher values of density, the curves diverge. This indicates the importance of equations that can unambiguously describe PCP to a relative density equal to or close to 1.0. For an adequate description of PCP for relative density greater than 0.95, equations containing three or four constants have proven useful.

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