Development of a new model describing the anisotropic dimensional change on sintering

Abstract

The anisotropic dimensional changes during sintering was investigated for rings made of eight different materials with different green densities and H/(Dext-Dint) ratio. Dimensional changes are affected by green density, as shown in previous works, while the geometrical parameter does not display a clear influence. The anisotropy parameter K defined in a previous work does not describe anisotropy of dimensional change unambiguously, due to the anisotropy of shrinkage/swelling in the compaction plane. A new anisotropy parameter (K3D) was therefore defined considering the dimensional changes of internal diameter, external diameter, and height. This parameter display an unambiguous dependence on the equivalent isotropic dimensional change and will be used in further work to develop a predictive model for the prediction of the anisotropic dimensional change during sintering of parts with different green density and geometry.

A study of the anisotropy of dimensional change in the compaction plane during sintering of low alloyed cold compacted steels

“…These equations will be implemented in the design methodology proposed in [18], and the results will be presented in a future paper.…”

“…The general equation of the three surfaces is given by Equation (11), while the specific terms for Fe–Mo–C, Fe–Mo–Cu–C and Fe–Mo–Cu–Ni–C, respectively, are reported in Table 4 These equations will be implemented in the design methodology proposed in [18], and the results will be presented in a future paper.…”

“…The impact of the anisotropic dimensional change on design has been investigated by Cristofolini et al [17], who proposed a design methodology accounting for the anisotropic shrinkage. The procedure is based on an anisotropy parameter K. Recent experiments [18] have demonstrated that this approach does not succeed when the dimensional change is anisotropic in the compaction plane, and a new anisotropy coefficient K 3D has been defined. However, the comprehension of the mechanisms responsible for this anisotropy is not yet fully achieved.…”

“…The procedure is based on an anisotropy parameter K . Recent experiments [18] have demonstrated that this approach does not succeed when the dimensional change is anisotropic in the compaction plane, and a new anisotropy coefficient K 3D has been defined. However, the comprehension of the mechanisms responsible for this anisotropy is not yet fully achieved.…”

Design for sintering – A comprehensive study on anisotropic dimensional change on sintering

“…19 On the contrary, larger dimensional change in the compaction plane with respect to axial direction was observed in liquid-phase sintering Cu steels. 20,21 The influence of both material and geometry was studied in Cristofolini et al, 22,23 highlighting that, the larger the change in volume, the lower the anisotropy in dimensional changes, while anisotropy generally tends to increase on increasing the height of samples. The effect of green density was considered in Molinari et al, 24 highlighting the different densification mechanisms prevailing at low and high green density, in turn determining different dimensional changes.…”