Effect of contact alignment on shrinkage anisotropy during sintering: Stereological model, discrete element model and experiments on NdFeB compacts.

Abstract

This works aims at analysing the effect of alignment of particle contacts on the shrinkage anisotropy during sintering. A stereological model is proposed which relates the shrinkage anisotropy factor to the distribution of contact area orientations. The shrinkage anisotropy is further analysed by using a discrete element method (DEM) to simulate the sintering of isostatically compacted packings of aligned particle chains. Finally, the analysis is performed on experimental magnetically oriented NdFeB powder compacts. The stereological model predicts a higher shrinkage in the direction of preferentially aligned contacts, in agreement with DEM simulations and experimental results, where a shrinkage anisotropy factor close to 2 is observed.

Keywords

• Anisotropy
• Contacts
• NdFeB
• Shrinkage
• Sintering