Caractérisation rhéologique des gelées semi-solides des alliages Al-Si renforcés

Structures et propriétés des alliages brassés à l'état semi-solide -- La rhéologie des suspensions -- Aspects fondamentaux de la dispersion de particules dans un bain métallique -- Rhéologie des alliages et des composites aux fractions solides moyennes -- Rhéologie des gelées semi-solides de matériaux composites -- Matériaux à l'étude -- Appareillges et procédures expérimentales -- Comportement des composites à l'état liquide -- Comportement des composites à l'état semi-solide -- Résultats des essais de compression entre plateaux paralèles

Lubricants for High-Density Applications by Pressing at Moderate Temperatures

Peer reviewed: YesNRC publication: Ye

High-performance PM steels utilizing extra-fine nickel

Distribution of the alloying additives in powder metallurgy (PM) steels is a key element in achieving optimum sintered properties. Segregation must be avoided in order to ensure consistent part-to-part properties. Recent studies indicate that extra-fine nickel powders have a beneficial impact on the overall properties of nickel-copper-carbon PM steels. Therefore, the use of extra-fine nickel powder in segregation-free PM mixes could be an efficient way to optimize properties. To this end, the effect of the size and size distribution of two nickel powders on the physical and mechanical properties of two binder-treated steel powder premixes processed on a polit scale has been assessed. The properties of these two mixes are compared with those of a diffusion-alloyed mix of the same composition. Mechanical properties and dimensional change of the binder-treated mixes are shown to be superior to those of the diffusion-alloyed mix. The physical and sintered properties of the binder-treated mixes can be further improved by using extra-fine nickel powder (D\u2085\u2080 1.5\ub5m) instead of a standard size (D\u2085\u2080 8\ub5m) nickel powder.Peer reviewed: YesNRC publication: Ye

Effect of Temperature on the Mechanisms of Densification and Lubrication of P/M Powder Mixes

Peer reviewed: NoNRC publication: Ye

High performance lubricants for demanding PM applications

The achievement of high density at reasonable cost is without a doubt one of the major ques of the P/M industry. Hish density can be achieved through various processing mutes involving the shaping of the part and/or the sintering. In particular, single pressing methods such as warm compaction and die wall lubrication are known to give green density in the range of 7.2 to 7.5 g\ub7cm-3 depening on the powder formulation. Nevertheless, these pressing techniques normally require tighter control, are costly and may reduce productivity compared to conventional pressing method. More recently, new high performance lubricants were developed to achieve higher green density than conventional lubricant by cold compaction or temperature-controlled die compaction. This paper presents the green and sintered characteristics of these newly developed high performance lubricants in a laboratory and production scale. In particular, the compaction and ejection characteristics of these new lubricants ale compared to that obtained with other conventional lubricants.Peer reviewed: YesNRC publication: Ye

High Performance Iron Powder Mixes for High Density PM Applications

Peer reviewed: NoNRC publication: Ye

High Performance Lubricants for Demanding PM Applications

Peer reviewed: NoNRC publication: Ye

Shaping Stainless Steel Powders Using Die Wall Lubrication

Peer reviewed: YesNRC publication: Ye

Using binder-treatment technology for high-performance steel powder mixes

FLOMET technology is a binder treatment blending technique that consists of bonding fine particles of graphite, metallic additives and lubricants to the coarser iron particles using a solid organic binder. The main advantages of binder-treated mixes compared to conventional mixes are better flow, improved productivity and part consistency and reduced dusting and segregation. These attributes make bindertreated mixes well suited for high performance PM applications as well as other types of applications requiring mixes with excellent die filling characteristics. QMP introduced a family of binder-treated mixes in the mid 1990\u2019s. Since then, R&D efforts were pursued to continuously improve the properties of this type of mix and to develop better performing binder-treated mixes for specific applications. This paper reviews the physical, green and sintered properties of binder-treated materials. Particular attention is paid to the processing characteristics of these materials.Peer reviewed: NoNRC publication: Ye

Method To Detect Ethanol Vapor in High Humidity by Direct Reflection on a Xerogel Coating

International audienc