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Title: Detection of melting by X-ray imaging at high pressure

The occurrence of partial melting at elevated pressure and temperature is documented in real time through measurement of volume strain induced by a fixed temperature change. Here we present the methodology for measuring volume strains to one part in 10{sup −4} for mm{sup 3} sized samples in situ as a function of time during a step in temperature. By calibrating the system for sample thermal expansion at temperatures lower than the solidus, the onset of melting can be detected when the melting volume increase is of comparable size to the thermal expansion induced volume change. We illustrate this technique with a peridotite sample at 1.5 GPa during partial melting. The Re capsule is imaged with a CCD camera at 20 frames/s. Temperature steps of 100 K induce volume strains that triple with melting. The analysis relies on image comparison for strain determination and the thermal inertia of the sample is clearly seen in the time history of the volume strain. Coupled with a thermodynamic model of the melting, we infer that we identify melting with 2 vol.% melting.
Authors:
;  [1]
  1. Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States)
Publication Date:
OSTI Identifier:
22308848
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; CAMERAS; CHARGE-COUPLED DEVICES; MELTING; PRESSURE RANGE GIGA PA; PRESSURE RANGE MEGA PA 10-100; TEMPERATURE RANGE 0400-1000 K; THERMAL EXPANSION; THERMODYNAMIC MODEL; TIME DEPENDENCE; X-RAY RADIOGRAPHY