Densification Mechanism, Elastic-Plastic Deformations and Stress-Strain Relations of Compacted Metal-Ceramic Powder Mixtures (Review)

Abstract

The basic purpose of compaction is to obtain a green compact with sufficient strength to withstand further handling operations. The strength of green compact is influenced by the characteristics of the powders (apparent density, particle size and shape, internal pores etc.), the processing parameters (applied force, pressing type, and temperature) and testing conditions (strain rate etc.) Successful powder cold compaction is determined by the densification and structural transformations of powders (metallic powders, ceramic powders and metal-ceramic powder mixtures) during the compaction stages. In this paper, for understanding the factors that determine a required strength of compacted metal-ceramic powder mixtures, we present the densification mechanisms of different mixtures according to densification theories of compaction, the elastic-plastic deformations of mixture powders, the stressstrain relations and the relaxation behavior of compacted metal-ceramic composite parts and the particularities of each of them.

Optimal Performance of Mg-SiC Nanocomposite: Unraveling the Influence of Reinforcement Particle Size on Compaction and Densification in Materials Processed via Mechanical Milling and Cold Iso-Static Pressing

“…The higher maximal relative density and improved compressibility observed in the Mg-SiC nanocomposite containing submicron-sized SiC particles, as estimated through FEM calculations under various pressures, can be attributed to the input model parameters used in the simulation. Higher values of cohesion of material (d) and friction angle (β) for M10Sµ compared to M10Sn (see Table 3) indicated enhanced interlocking of M10Sµ constituent particles [29,30], which can be traced back to the microstructural characterization of the powder composite. M10Sn exhibited finer and equiaxed morphology after 25 h of mechanical milling (Figure 6a), while M10Sµ powder particles displayed a more irregular, flake-like morphology (Figure 6b) [31].…”

“…The cap eccentricity (R) in the MDPC model reflects the propagation of plastic flow among particles and their resistance to deformation or deflection under applied loads. It provides information about how the particles resist deformation or deflection under the given load [29]. The significantly lower cap parameter value for M10Sn, 0.53, compared to M10Sµ, 1.77, reveals the lower deflection and higher stiffness, i.e., higher resistance to permanent plastic deformation [30] of the composite containing the nanoparticles under the same load.…”