Material testing

The Material Testing facility represents one of the most versatile laboratories of its kind, dedicated to the mechanical and rheological investigation of geological and technical materials under extreme conditions. Our infrastructure enables precise quantification of material behavior across a vast operational envelope—from high-energy ballistic impacts and earthquake rupture simulations to mineral physics studies at mantle pressures using Diamond Anvil Cells (DAC). By combining uniaxial, triaxial, and rotary shear systems with high-temperature rheometry, we provide the empirical data necessary to model the deformation of magmas, glasses, and rocks across temperatures up to 1250°C and forces ranging from millinewtons to hundreds of kilonewtons

Mineral Physics

The Mineral Physics Preparation Lab is dedicated to preparing diamond anvil cells (DACs) for studying the properties of materials under extreme pressure and temperature conditions. Research focuses on the structural, physical, and thermodynamic behavior of crystals (minerals and functional materials), melts, glasses, and aqueous fluids, as well as their interactions.

Instrumentation

• Boehler-Almax Diamond Anvil Cells: For high-pressure diffraction and spectroscopic analyses of solids (0–50 GPa), compatible with high- and low-temperature setups.
• Bassett-type Hydrothermal Diamond Anvil Cells (HDAC): For high-pressure and high-temperature studies of fluids (0–1 GPa, 300–1000 K).
• Electrical Discharge Machining (EDM): For precise drilling of DAC and HDAC gaskets.

Rock Mechanics and Magma Rheology

The Rock Mechanics and Magma Rheology Laboratory is a central hub for the mechanical, geophysical and rheological investigation of rocks, magmas, metals, glasses, cements, clastic systems, and soils. This laboratory contains a wide spectrum of standard and bespoke apparatus and tools for physical characterisation as well as mechanical and rheological testing at a wide range of pressure (<100 MPa), temperatures (<1200 ˚C) and dynamic conditions (compression, tension, torsion, oscillation (<100Hz), fluid pressure, etc). Together with apparatus in the Thermal Analysis Laboratory and in the Ballistic and High-Energy Impact Testing Laboratory, this facility can test material at a range of dynamic applied forces (3 mN-300 kN) and testing rates (sub-micron/s to 60 m/s). It is one of the largest and most versatile testing facilities of its kind.

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This large uniaxial press can be used to determine the compressive and tensile strength of materials (indirectly trough Brazilian test) and the viscosity of multiphase magmas using the parallel-plate method. This press permits testing at the following conditions:

Force: 300 kN

Strain rate: 10^-6 to 10^-1 s^-1

Oscillation: < 1 Hz

Temperature: < 1000 °C

Samples size (in compression): D20-75mm, L40-500m or D180mm; L180mm

Capabilites: acoustic emissions, sapphire window for thermographic imaging, radial extensometer, volumetric strain

Ballistic and High-Energy Impact Testing

The ballistic and high-energy impact testing apparatus form part of the Dynamic material testing laboratory. This bespoke apparatus was designed to test materials’ response to high energy impacts, as experienced during volcanic ballistic collision (with rocks and building materials), during earthquake rupture and during small meteorite impacts.

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This apparatus can be used to determine the mechanical response of materials to impact at both ambient and high temperature. Impact energy is controlled by varying mass of the impactor or drop height (~velocity). Customisation allows the rapid retrieval of the impactor after first impact, as well as quenching of the sample immediately after impact.

Force: up to 222 kN

Energy: up to 1800 J

Mass/ Velocity: <70kg / <24m/s

Temperature: <1200 °C

Sample geometry: >40mm height

Capabilities: acoustic emissions, high speed imaging

Rheometry and melt density

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We have 3 concentric cylinder viscometers to measure the viscosity of silicate melts at high temperature (up to ~1500 °C). The viscometer consists of a RVTD Brookfield head, which connect and drive a Platinum spindle (at constant speeds between 0.5 and 100 rpm) inside a molten sample held in an oven, whilst digitally recording the torque exerted on the spindle by the sample. The sample is held in a Platinum crucible (~2.5cm diameter by ~5cm high) in one of there furnaces; one of which permits measurement in exotic chemical atmospheres, located in the gas-mixing laboratory.

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The modular rotational rheometer is optimized for advanced research, R&D, and material characterization. It is designed to perform steady, oscillatory, and dynamic rheological tests in torsional configuration via the concentric cylinder method or the parallel-plate method. It is possible to measure viscosities of ultra-low viscosity fluids such as aqueous solutions and carbonate melts. Furthermore, it could be used to study the non-Newtonian viscosity of silicate melts, containing bubbles and/ or crystals.

Parameter (Typical Value / Range):
Working temperatures: 20-1000 °C
Atmosphere chemistry (Gas flow): Argon (5.0) at 25 cm/min
Maximum torque: up to 230 mN·m (instrument range)
Minimum torque: ~1 nN·m (rotation) / ~0.2–0.5 nN·m (oscillation)
Torque resolution: ~0.05 nN·m
Angular deflection resolution: < 1 nrad
Angular velocity: 10 to 314 rad/s (~0 to >200 rad/s depending on model)
Frequency range (oscillation): ~10⁻⁸ Hz to 200 Hz
Normal force range: ~0.001 N to 50 N
Normal force resolution: ~0.1 mN

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The Netzsch TMA F1 thermomechanical analyser is a flexible rheometer which can be used to measure viscosity via the parallel-plate method and via micro-penetration, measuring viscosities in the range of 10⁷ to ~10¹² Pa s. The methods are employed in different setup configurations, using alumina assembly to deform a sample (disc or core) under isothermal conditions. The viscosity is directly correlated to the applied stress and deformation rate or the indentation rate, respectively. The device accommodate a range of furnaces (ceramic, platinum) and can be connected to a water vapor generator to measure under humid conditions. The device can be use under the following conditions:

• Temperature: up to 1550 ˚C
• Atmopshere chemistry (gas flow): Ar (5.0), N at 25 cm³/min, and H₂O
• Force: 3mN-3N

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The experimental setup makes use of Archimedes method to measure the density of liquids at high temperautre. In this setup, a platinum spindle connected to the underside of a high-precision balance is lowered into a melt, held in a platinum crucible placed within a furnace (operating up to 1500 °C).