highSSM – High Specific Stiffness Materials
The ESA-project “highSSM” covers the search and testing for novel metallic materials with high specific stiffness.
The main objective of the project was to select the most promising metallic based composites (MMC) which have a high specific stiffness (> 34 x106 m2/s2) to be used on planetary spacecraft such as for Mars surface missions. These materials have been evaluated to establish their performance in both Earth and Martian environments. In this connection a wide ranging review which included more than 150 candidates followed by a trade-off study considering the different technical properties, manufacturing and economic issues as well as environmental impact have been carried out. The results obtained showed that Al- and Ti-alloys based composites reinforced by particles and fibres respectively promise the best performance. The selected materials have been tested with respect to the microstructure as well as to the mechanical, corrosion and CTE properties upon earth environment taking into account behavior in different directions. Based on the findings from the earth test campaign two materials have been down selected for the tests which considered mars environment such as temperature and CO2 atmosphere. The study performed enabled to identify a high potential of Al-alloy reinforced by SiC particles and Ti-alloy reinforced by SiC fibres for applications requiring besides a high specific stiffness also adequately high mechanical and physical properties. Hence these materials can be considered as a replacement for the conventional materials e.g. for Ti6Al4V alloy.
A paper will be published to the ISMSE conference (International Symposium for Materials in Space Environment 2015).
Light microscopic images: Cross sections of 640xa, TiSiC , Ti64 –TiB2, Al-Cf respectively