Analysis of the Cold Compaction Behavior of Titanium Powders: A Comprehensive Inter-model Comparison Study of Compaction Equations

Machaka, Ronald; Chikwanda, HK

doi:10.1007/s11661-015-3038-6

Cited by 22 publications

(17 citation statements)

References 48 publications

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“…An extensive list of equations mostly designed for metal or pharmaceutical powder compactions is reviewed in [58][59][60]. Although the previous models provide acceptable predictions on specific cases, their limitations are due to (i) the use of parameters with no clear physical meaning, (ii) the lack of physical derivation, and, for many among them, (iii) the limitation to a single solid granular phase.…”

Section: Introductionmentioning

confidence: 99%

Compaction of mixtures of rigid and highly deformable particles: A micromechanical model

et al. 2020

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We analyze the isotropic compaction of mixtures composed of rigid and deformable incompressible particles by the nonsmooth contact dynamics approach. The deformable bodies are simulated using a hyperelastic neo-Hookean constitutive law by means of classical finite elements. We characterize the evolution of the packing fraction, the elastic modulus, and the connectivity as a function of the applied stresses when varying the interparticle coefficient of friction. We show first that the packing fraction increases and tends asymptotically to a maximum value φ max , which depends on both the mixture ratio and the interparticle friction. The bulk modulus is also shown to increase with the packing fraction and to diverge as it approaches φ max . From the micromechanical expression of the granular stress tensor, we develop a model to describe the compaction behavior as a function of the applied pressure, the Young modulus of the deformable particles, and the mixture ratio. A bulk equation is also derived from the compaction equation. This model lays on the characterization of a single deformable particle under compression together with a power-law relation between connectivity and packing fraction. This compaction model, set by well-defined physical quantities, results in outstanding predictions from the jamming point up to very high densities and allows us to give a direct prediction of φ max as a function of both the mixture ratio and the friction coefficient.

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Section: Introductionmentioning

confidence: 99%

Compaction of mixtures of rigid and highly deformable particles: A micromechanical model

et al. 2020

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“…The numerical results of SC packing structures for Cu solid and sponge particles-based powder with various internal pores content and different initial packing structures during the cold compaction are fitted by using double logarithmic equation given by [35]:r r r r r r…”

Section: Resultsmentioning

confidence: 99%

“…Gerdemann et al [34] compress the spongy particles-based powder and different titanium powders to collect stress and deformation data during the cold compaction in a single-acting die. Machaka et al [35,36] analyzed the behavior and mechanisms of densification in sponge titanium powder and selected nanocomposite titanium powder samples by means of the comprehensive inter-model comparison of existing compaction equations.…”

Section: Introductionmentioning

confidence: 99%

Study the densification behavior and cold compaction mechanisms of solid particles-based powder and spongy particles-based powder using a multi-particle finite element method

Korim

2020

Mater. Res. Express

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Powders could be based on solid particles or spongy particles depending on the powder manufacturing procedures. In this article, the numerical study of the cold compaction process for copper solid particles-based powder (i.e. Cu solid powder) and spongy particles-based powder (i.e. Cu sponge powder) has been carried out by using a two-dimensional multi-particle finite element method (2D-MPFEM) based on single action die compaction. The effects of internal pores content, external pressure, initial packing structure on the packing densification were systematically presented. Relative density, stress distribution, internal pore deformations, and force chain movements, particle rearrangement, and interfacial behavior within spongy particles were characterized and analyzed. The results reveal that the densification behavior of the sponge powder depends basically on the internal pore's content. Moreover, at low and medium relative density (ρ <0.95), the densification behavior of the sponge powder is faster than solid particles-based powder. However, at higher relative density near unity, the force required to cause further compaction is significantly larger in the sponge powder. In addition, from the microscopic analysis, the deformation behavior of the particles and the internal pores and the force chain development rely mostly on the structure configuration, internal pore content and its position.Recently, powder metallurgy (PM) becomes an appealing process technology for both advanced and traditional materials [1]. The PM technique is competitive with conventional metallurgical manufacturing methods such as casting, forging, and machining. Moreover, it has distinctive merits such as high production rate and near-netshape forming for complex geometrical shapes, special metals, alloys with high melting points, and porous structures. In addition, it can be considered cost-effective, materials saving, easy operation, and environmentfriendly mechanism [2]. Thus, PM techniques have a lot of applications that can be used in the areas of materials, marine industries, aeronautics, astronautics, and automotive parts [3]. Powder cold compaction is one of the major stages of PM production processes that plays a key role. Through the compaction, loose powders are compressed into a cohesive and dense state using tools such as compression punches and dies [4]. The powder compact structure resulting from the powder cold compaction affects the sintering process and the properties of the final product. Therefore, any optimization of the powder compaction process requires a deep understanding of the relations between the influential factors and the densification behaviors during the powder compaction process. Consequently, a large variety of physical and numerical studies have been carried out in this regard.It is very complicated for physical experiments to characterize parameters and properties of the green compacts such as the evolution of stress distribution and local relative density and plasticity and elasticity phenomena [5]. ...

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“…In an investigation of 11 different compression equations Adams' model was excluded because the model was "generally over-parameterized". 25 This statement is, in an Ockham context, worthwhile to investigate. Furthermore, it is concerning that the Adams' model may estimate a strength of granules where no granules are present.…”

Section: Alternative Modelsmentioning

confidence: 94%

Ockham's Razor Applied on Pharmaceutical Powder Compaction Models

Møller-Sonnergaard

2021

Journal of Pharmaceutical Sciences

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This investigation contains a critical survey of a collection of five well-known and often used standard models in pharmaceutical technology. The basic idea is to use the recognised Ockham's razor as a tool in search for simpler methods or explanations for these models. The study includes the indirect tensile strength of tablets, Pitt's equation for tensile strength of biconvex tablets, Adams' model for strength of agglomerates, Weibull's distribution for variability of strength measurements and Heckel's equation for compressibility. In all these cases simpler and equally valid solutions and explanations are presented and subsequently preferred rather than the original.

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Analysis of the Cold Compaction Behavior of Titanium Powders: A Comprehensive Inter-model Comparison Study of Compaction Equations

Cited by 22 publications

References 48 publications

Compaction of mixtures of rigid and highly deformable particles: A micromechanical model

Compaction of mixtures of rigid and highly deformable particles: A micromechanical model

Study the densification behavior and cold compaction mechanisms of solid particles-based powder and spongy particles-based powder using a multi-particle finite element method

Ockham's Razor Applied on Pharmaceutical Powder Compaction Models

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