Laser interferometric dilatometer for low-expansion materials
The development of a high-precision dilatometer based on interferometry presents a number of challenges. This paper describes a laser interferometric dilatometer developed for high-precision thermal expansion measurements in the materials laboratory. The Sandia dilatometer uses dual-beam laser interferometry with a computer-controlled optical alignment feature to achieve high-precision length change measurements. This device has been modified to expand its measurement capabilities in a number of areas. A new thermal chamber has been incorporated which provides a range of measurement from 90 to 500 K while minimizing thermal effects on the optical portion of the instrument. A new specimen holder has been developed to cover this temperature range while accommodating a wider variety of specimen types. In particular, thin (1-mm) composities may be employed in the holder, which uses a single specimen, with only modest shape and preparation requirements, to provide absolute length change measurements. Tilt errors limit the overall performance of dilatometers based on dual-beam interferometry. Significant improvements in precision were demonstrated by incorporating a unique optical system which independently measures specimen holder tilt; tilt errors were corrected and a length change resolution near 0.4 ..mu.. strain was achieved. Expansion coefficient data obtained with the device agreed with established results on fused silica and stainless steel. New expansion data were obtained from 90 to 293 K on stainless steel, NBS Standard Reference Material 738.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- OSTI ID:
- 6293503
- Report Number(s):
- CONF-880606-
- Journal Information:
- Int. J. Thermophys.; (United States), Vol. 9:5; Conference: 10. symposium on thermophysical properties, Gaithersburg, MD, USA, 20 Jun 1988
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
47 OTHER INSTRUMENTATION
INTERFEROMETERS
RESOLUTION
SILICA
DILATOMETRY
STAINLESS STEELS
BEAM OPTICS
CALIBRATION STANDARDS
COMPUTERIZED CONTROL SYSTEMS
DESIGN
HELIUM-NEON LASERS
INTERFEROMETRY
LEAST SQUARE FIT
OPTICAL SYSTEMS
PERFORMANCE
SAMPLE HOLDERS
TEMPERATURE MEASUREMENT
THERMAL CYCLING
THERMAL EXPANSION
ALLOYS
CHALCOGENIDES
CONTROL SYSTEMS
EXPANSION
GAS LASERS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
LASERS
MAXIMUM-LIKELIHOOD FIT
MEASURING INSTRUMENTS
MINERALS
NUMERICAL SOLUTION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
STANDARDS
STEELS
THERMAL ANALYSIS
360104* - Metals & Alloys- Physical Properties
440300 - Miscellaneous Instruments- (-1989)