An in situ thermo-mechanical rig for lattice strain measurement during creep using neutron diffraction

Abstract

A long-term high-temperature testing stress rig has been designed and fabricated for performing in situ neutron diffraction tests at the ENGIN-X beamline, ISIS facility in the UK. It is capable of subjecting metals to high temperatures up to 800 °C and uniaxial loading under different boundary conditions including constant load, constant strain, and elastic follow-up, each with minimum of external control. Samples are held horizontally between grips and connected to a rigid rig frame, a soft aluminium bar, and a stepper motor with forces up to 20 kN. A new three zone split electrical resistance furnace which generates a stable and uniform heat atmosphere over 200 mm length was used to heat the samples. An 8 mm diameter port at 45° to the centre of the furnace was made in order to allow the neutron beam through the furnace to illuminate the sample. The entire instrument is mounted on the positioner at ENGIN-X and has the potential ability to operate continuously while being moved in and out of the neutron diffraction beam. The performance of the rig has been demonstrated by tracking the evolution of lattice strains in type 316H stainless steel under elastic follow-up control at 550 °C.

A Unique Quenching and Deformation Dilatometer for Combined In Situ Neutron Diffraction Analysis of Engineering Materials

“…This includes devices such as specialized load frames including rapid infrared heating at the diffractometer ENGIN-X (ISIS, UK) or induction heating at the neutron strain scanner VULCAN (SNS, USA), respectively. [15,16] A quite unique instrumentation is the thermomechanical processing simulator at BL19 TAKUMI (J-PARC, Japan). [17] Using this particular device, many studies related to phase transformations kinetic, texture evolution, and developing mechanical properties in alloys have been conducted successfully in recent years, highlighting the demands for this kind of in situ studies.…”