Heavy Testing Machines
A 250 Tonne hydraulic forming press and 100 Tonne high-speed (up to 1.6 m/s) hydraulic forming press are available. These machines can act in tension and compression and can be used for three-point bending tests and forging tests. The 100 Tonne high-speed press can also be used for large scale fatigue tests. The force transducers of the 100 Tonne press have exceptional hysteresis performance and can record load at the highest strain with little noise. The machines can be fitted with furnace heaters that allow controlled high temperature testing (up to 1200 °C).
Thermomechanical Fatigue systems
Thermomechanical Fatigue (TMF) systems simulate the complex effects of thermal-cycling combined with mechanical-loading, normally experienced by gas turbines and similar equipment during operation. More sophisticated than isothermal fatigue, TMF testing helps to better evaluate the life of many materials and engineering components that are used in high-temperature applications. A dynamic heating and cooling system is combined with a high-temperature materials testing system to achieve complex mechanical and thermal cycling.
High Rate Testing Machines
There are 25 Tonne (up to 5 m/s) and 2 Tonne (up to 25 m/s) testing machines available for high strain rate tests. These machines are important for studying strain-rate dependant effects and can be used for ballistics research.
A new gas gun has been installed in the lab. The gas gun has a fast launching mechanism allowing firing ice balls as well as rubber and gelatine projectiles. The gas gun can be connected to both compressed air and helium to the pressure up to 10 bar. The target area is designed with polycarbonate windows allowing the strain mapping of the sample under impact. The gun has 3 m long barrels in three different diameters including 10, 25 and 40 mm.
Gleeble Thermal-mechanical Simulator
The Gleeble 3800 is a fully integrated digital closed loop thermal and mechanical testing system. Specimens can be heated at rates up to 10,000 °C/s by resistance heating, or can be held at constant temperature. It is capable of exerting up to 20 Tonne of static force in compression or 10 Tonne in tension, with applied displacement rates up to 2 m/s. Feedback consists of linear variable differential transformers, load cells or non-contact laser extensometry.
Optical Strain Mapping
The optical techniques available within the Centre include Digital Image Correlation (including Speckle and Grid Patterning), Electronic Speckle Pattern Interferometry and Moiré Interferometry. Digital Image Correlation provides 3D deformation mapping.
A wide range of X-ray diffraction techniques are available within Imperial College for the investigation of polycrystalline materials, single crystal and thin films. Samples may be examined in either bulk or powdered form. There are currently 2 PANalytical MRDs, 2 PANalytical MPDs and a Bruker D2 desk-top instrument for rapid data collection. There is also a high temperature X-ray diffraction facility. X-ray diffraction measurements can be performed at elevated temperatures up to 1000 °C using a combination of direct and indirect heating. This allows the investigation of the thermal behaviour of lattice parameters, crystallisation studies, and the detection and characterisation of high temperature phases. The high temperature chamber is fitted with a system to allow measurements to be made in controlled atmospheres (including oxidative) so that structural changes related to sample-gas interactions can be studied.
The highly penetrative neutron diffraction technique is well established for measuring 3D residual stresses deep within in a volume of material, non-destructively. Imperial have widely employed the technique to measure macro scale residual stresses and strains, typically in welded on non-uniformly plastic deformed components. These measurements have been valuable for the verification of finite element models to simulate the welding or deformation process and predict the residual stress fields. The method has also been employed to measure intergranular strains in alloys and used to develop and verify crystal plasticity models. Imperial have been greatly successful in being awarded beam time at a number of research institutes including ISIS, UK; Helmholtz-Zentrum, Berlin; Institut Laue-Langevin, France; Heinz Maier-Leibnitz, Munich and The Paul Scherrer Institute, Switzerland.
Harvey Flower Microstructural Characterisation Suite in the Department of Materials for electron microscopy provides modern facilities for advanced materials imaging and characterisation. The facilities include three scanning electron microscopes (SEMs) and three transmission electron microscopes (TEMs). This includes the state-of-the-art monochromated FEI TITAN 80/300 and FEI Helios NanoLab 600 DualBeam TEM. In addition, a dedicated microscopy team maintains the latest technology in the two sample preparation labs and data processing suite.