The Effect of Nitrogen Linear Flow on Lubricant Removal and Sintering Densification of Alumix 431D Grade Powder

Abstract

ECKA Granules Alumix 431D commercial grade, press ready, pre-alloyed aluminium-based powder containing 1.5 mass% of Acrawax C was used to study the effect of nitrogen linear flow on de-lubrication and sintering densification. In situ dimensional changes were controlled by dilatometry. Microstructural observations of sintered compacts were also performed. The results clearly showed the strong influence of nitrogen linear flow on de-lubrication, and thus on the sintering behaviour of the examined powder. High nitrogen linear flow is required to produce the desired sintered microstructure—characterised by residual porosity. In contrast, at low nitrogen velocity, the lubricant removal is not complete, which in turn significantly impedes densification.

Keywords

• powder metallurgy
• lubricant removal
• dilatometry