SpAACe

Starting point / motivation

All materials used in space applications have to fulfil a number of sometimes conflicting requirements such as mass, stability, strength, stiffness, and radiation resistance. Although materials used in space are not different from those for terrestrial application, the operational environment with its high energetic particles and ionizing radiation from sun, vacuum, large thermal variations or high velocity debris and meteoroids differs greatly.

In special, space structures require the usage of thermally stable materials with high density-specific stiffness and high density-specific strength. These have to operate in harsh space environment with limited degradation in order to fulfil space requirements and at the same time be able to save mass, space and costs. Currently the launch of 1 kg payload costs ~€25.000 to €30.000.

Contents and goals

Metal Matrix Composite (MMC) materials especially long fibre reinforced MMC´s offer such unique combination of material properties. A lot of MMC materials were investigated by the scientific community worldwide but limited commercial products are on the market, especially for long fibre reinforced parts and especially from European suppliers (TiSiC from UK for SiC-long-fibre reinforced Titanium matrix MMC´s) to date. The reason for this is the difficulty of stable production leading to high production costs, the difficulty to achieve combined high specific stiffness and strength and the currently small market for such materials.

Project-aim of SpAACe is the development and validation of long fibre reinforced Al and Mg alloys showing the potential for combined high specific stiffness, strength and thermal stability (very low thermal expansion) for space application like planetary landers or thermally stable structures (struts for telescopes). These are currently not available on the market.

Methods

In first screening tests performed within the ESA project HighSSM led by AAC, promising results of a continuous, carbon-fibre reinforced Aluminium-matrix MMC produced by LKR Ranshofen (Austria) have been demonstrated. Especially LKR´s Al-MMCs have shown highest specific stiffness and lowest thermal expansion in comparison with other investigated, most promising European MMC materials.

However when looking at the theoretical, potential values in specific stiffness and strength these values can be exceeded by 30% in density-specific stiffness and 200% in density-specific strength with an adopted and enhanced process compared to results achieved within this first characterized prototype material.

Expected results

Within the described research project, advanced manufacturing methods will be used as well as enhanced matrix systems (carbon nanotubes, graphene modified aluminium or inflammable Mg-alloys), infiltration process simulations for improvement of process stability, and advanced testing methods (e.g. online acoustic emission monitoring for early damage detection).

This will assist the development of a class of materials which exceeds the specific stiffness and strength of TiSiC-MMC by a factor 2.5 respectively 2.0. In case such material development leads to the expected results in specific stiffness and specific strength, structures such as kinematic mounts for optical instruments, fittings for struts, actuators or drives for planetary landers could be produced with weight reduction potential between factors of 3 to 5 compared to current baseline solution made of TiAlV64.

Coordinator

LKR Leichtmetallkompetenzzentrum Ranshofen GmbH

Project partner

Aerospace & Advanced Composites GmbH

LKR Leichtmetallkompetenzzentrum Ranshofen GmbH
DI(FH) Hubert Grün
Lamprechtshausenerstraße 61/26
A-5282 Ranshofen