Papers by Keyword: Architectured Materials

Abstract: The architectured metallic materials are a class of composite materials that combines two or more metals/alloys with a specific spatial ordering (architecture). The main goal behind the preparation of such materials is to obtain properties that are not achievable by a single material. The internal architecture thus creates an extra degree of freedom in materials design. Based on theoretical considerations three aluminum alloy structures containing square, triangle and sinusoidal iron beam patterns have been prepared by a cold spray deposition technique. Strength properties difference and good bonding of the reinforcing Fe structure to the Al matrix has been found to be important for effective improvement of final properties. Incorporating about 30 vol. % structured iron beams into the Al matrix resulted in a macroscopic performance of the architectured multimaterial similar to Ti alloys.

Abstract: Spark plasma sintering has been used for decades in order to consolidate a wide variety of materials and permitting to obtain fully dense specimens. This technique has been mainly applied to ceramics. This paper concentrates on an unusual use of spark plasma sintering system: obtaining innovative materials especially architectured ones. Different applications are presented. Firstly, the SPS technique has been used to elaborate nanometers grain size materials or containing nanoscale microstructure. This is possible since the sintering temperature and the holding time are far lower in the SPS compared to other techniques. Then SPS has been used to realize diffusion bonding. In that case again, bonding can be realized at low temperature and for short time. It permits for example to realize bonding between two copper layers which is of a great importance for microelectronic applications. It is worth noting that this bonding can have the same mechanical strength as pure copper even for diffusion time of a few minutes. Secondly, bonding has been also carried out between a metallic layer and a ceramic one. This could lead to design of new layered materials combining interesting properties in terms of mechanical strength but also in terms of electrical resistance. The SPS machine has also been used to obtain porous materials (cobalt alloys or copper) with an adapted microstructure (porosity, tortuosity,). These structures could open new perspectives for biomedical or for microelectronic applications. All these examples lead to a better understanding of the physical processes which happen during spark plasma sintering.