Key Areas

Ageing
All materials age. Ageing effects can vary depending upon conditions, especially in the extreme environments found within nuclear warheads. Dedicated project teams across Materials Science have been formed to investigate, model and predict ageing effects in materials. 

Techniques are being developed throughout the materials areas to predict future behaviour. Considerable effort is being employed to develop and validate science-based models and techniques of accelerating age effects. Accelerated ageing and the validated models will be used to predict service-life issues and identify any long term performance or compatibility effects.

Stockpile Stewardship
Materials Science provides a technical response to stockpile issues. This includes stockpile surveillance (evolved gas analysis from capsule atmospheres, corrosion analysis, and materials characterisation from service returns). Surveillance is undertaken to gather information on all aspects of materials behaviour and is used to underwrite the stockpile.

Trials and Diagnostics
In order to provide continuous improvement to the stewardship of the UK current and future stockpile of nuclear weapons, it is necessary to develop and apply new and existing sensor technologies to the particular and sometimes unique issues and problems arising from the complex chemistry of material ageing. Utilising such diagnostic tools will enable us to monitor and assess both the ongoing chemical and physical/mechanical changes that occur during the service life of a warhead.

Current areas of interest are trace gas detection for both permanent and organic vapours, surface condition monitoring (corrosion), monitoring changes in mechanical properties and shape changes.  Current Sensor Technologies include Fibre optics (Fibre Bragg Gratings), Raman spectroscopy (gas and surface analysis), Infra-red spectroscopy (gas and surface analysis), Laser absorption (gas analysis), Solid state gas sensors, Pressure, and Temperature.  Sensors must be sensitive and accurate, stable, durable and robust, allow in-situ integration and be portable, safe and amenable to miniaturisation.

Compatibility
Material and chemical interactions are assessed throughout the warhead and sub-component interfaces to ensure compatibility is achieved. Materials are assessed for compatibility prior to introduction into systems designs. Materials Science is responsible for compatibility testing of materials and has developed a range of specialist analytical equipment, techniques and expertise to ensure compatibility is achieved.

Mechanical testing
The division is host to an extensive material testing capability. Examination of materials to determine fundamental physical properties such as tensile strength and Young's modulus leading to determination of fracture toughness and ultimately failure mode modelling is undertaken. Specially modified equipment enabling measurement in exotic environments, such as hydrogen, has been developed.

Materials Modelling
Materials Science Research has a world-class materials theory and modelling capability to calculate materials structure and properties over many length scales. Modelling ranges from: quantum mechanics (total energies, magnetic, electronic, thermodynamic and transport properties), atomistic simulation applied to defects and diffusion in solids (radiation damage, ion implantation, dopant diffusion), phenomenological modelling of processes (material failure such as crack propagation, fatigue), continuum modelling and other theoretical work, to produce component and system models to predict both ageing and performance.