Lightweight, controlled expansion alloy used in BAMSE anti-missile, missile defence system

Citation

(2005), "Lightweight, controlled expansion alloy used in BAMSE anti-missile, missile defence system", Aircraft Engineering and Aerospace Technology, Vol. 77 No. 1. https://doi.org/10.1108/aeat.2005.12777aad.003

Lightweight, controlled expansion alloy used in BAMSE anti-missile, missile defence system

Lightweight, controlled expansion alloy used in BAMSE anti-missile, missile defence system

Keywords: Aircraft components, Alloy

In order to reduce component weight, Saab Bofors Dynamics have selected an aluminium-silicon alloy from Sandvik Osprey for tubular shaped, bearing housings in their newly developed, anti-missile, missile defence system known as BAMSE.

The density of the new alloy (designated Osprey CE14), is one third that of steel and results in considerable weight saving and performance enhancement in a critical part of BAMSE, namely the rapidly moving, radar guidance drive unit. Furthermore, the coefficient of expansion of the alloy (14 ppm/C) has been specifically tailored by Sandvik Osprey to match the expansion of several steel components that remain in the system. Whilst Saab considered the possible use of aluminium-beryllium alloys, the CE14 alloy was selected due to its relatively low cost, ease of fabrication and freedom from health and safety issues during machining.

Saab Bofors Dynamics have recently completed their development programme and have, therefore, entered the commercial phase where several units are currently being manufactured for use in defence systems worldwide.

Controlled expansion (CE) alloys are produced by Sandvik Osprey's proprietary spray process, which results in fine, uniform microstructures of silicon particles distributed in aluminium matrices, thereby imparting isotropic properties to the products together with good machinability. The series of Al/Si CE Alloys, with compositions in the range 27 per cent to 70 per cent Si, originally developed by Sandvik Osprey, are now becoming widely used for carriers and housings in electronic packaging, particularly in the aerospace and defence fields.

Their main attraction for these applications is their low density (typically 5-10 per cent less than conventional Al alloys), high thermal conductivity (up to 180 W/mK) and controlled expansion coefficients (7-17 ppm/C depending on composition). Several of the alloys are said to exhibit useful mechanical properties, particularly specific stiffness, which, combined with low density and a high thermal stability, are leading to the development of structural applications such as the BAMSE housings. For such applications, the near-net shaping ability of Sandvik Osprey's processing technology enables billet, bar and tubular shapes to be readily produced (Plate 1).

Plate 1 Bearing housings made from Sandvik Osprey controlled expansion alloy

For further details contact: Sandvik Osprey Ltd, Osprey CE Alloys Group. Tel: +44 (0)1639 634121; Fax: +44 (0)1639 630100; E-mail: cealloys.osprey@sandvik.com, Web site: www.ospreymetals.co.uk