No abstract

The quality of powder used in powder bed-based additive manufacturing plays a key role concerning process performance and end part properties. Even though this is a generally accepted fact, there is still a lack of a comprehensive understanding of the powder property-part property relationship. However, numerous investigations focusing on selected powder properties and their corresponding influence on process aspects or final part properties have been published in recent years. Still, generalized statements on powder requirements for a defined process performance are not available. This can be attributed to the fact that the community has not yet come to an agreement which characterization techniques are most suitable for powder characterization in the additive manufacturing context and in most cases only selected aspects have been investigated for special powder materials. The aim of this review is to assess these building blocks of knowledge and to provide an overview on the current state of the art.

No abstract

Thermal aspects are becoming increasingly important for the reliability of the electronic components due to the continuous progress of the electronic industries. Therefore, the effective thermal management is a key issue for packaging of high performance semiconductors. The ideal material working as heat sink and heat spreader should have a CTE of (4-8) × 10 −6 K −1 and a high thermal conductivity. Metal matrix composites offer the possibility to tailor the properties of a metal by adding an appropriate reinforcement phase and to meet the demands in thermal management.Copper/SiC and copper/diamond composites have been produced by powder metallurgy. The major challenge in development of Cu/SiC is the control of the interfacial interactions. Silicon carbide is not stable in copper at the temperature needed for the fabrication of Cu/SiC. It is known that the bonding between diamond and copper is very weak in the Cu/diamond composite. Improvements in bonding strength and thermo-physical properties of the composites have been achieved by • a vapour deposited molybdenum coating on SiC powders to control interface reactions, • using atomized Cu(X) alloys with minor additions of carbide formers, e.g. X = Cr, B, to improve the interfacial bonding in Cu-diamond composites.