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Title: INVESTIGATION OF ELASTIC AND THERMAL PROPERTIES OF CARBON-BASE BODIES

Abstract

Results are presented of a first year of a program designied to study the elastic and the conductive properties of toe carbon-base materials. A high precision apparatus for study of flexure and torsion deformations at room temperature with dependence on iime and the applied stress was developed, and complete stress-strain hysteresis type curves obtained. Prescnce of creep and permanent set both increasing in proportion to the logarithm of timc has been established. Furthermore, it has been found that the presence of the original extruded surface contributes to ihc shear but not to the Young's modulus. Noises originating from formation of cracks during the firsi deformation were listened to in an effort to undersiand the nature of creep and permanent set under these conditions. A direct determination of Poisson ratio for compression along ihe extrusion axis gave a result delta = 0.14 the J-57 engin 0.02. The velocity of ultrasonic waves has been found to depend strongly on the density of the graphite, but not on the frequency of the waves. An apparatus for the study of heat conductivity at high tempratures (1200 to 3000 C) was;onstructed and operated with either an argon atmosphere or under evaeuated eonditions. A number ofmore » representative types of carbon materials (soft and hard carbons, and mixed composites)s has been studieds and it was shown that the conductivity mainly depends on the particle type and less on the binder type used in ihe mix. Convection of gas contained in pores contributes to the measured over-all conductivity. No particle size dependence could be found. (auth)« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Buffalo. Univ. Carbon Research Lab.
OSTI Identifier:
4278067
Report Number(s):
WADC-TR-58-360(Pt.I); AD-20666
NSA Number:
NSA-13-011189
DOE Contract Number:
AF33(616)-5186
Resource Type:
Technical Report
Resource Relation:
Other Information: Project title: CERAMIC AND CERMET MATERIALS. Task title: ANP ROVER MATERIALS. Orig. Receipt Date: 31-DEC-59
Country of Publication:
United States
Language:
English
Subject:
METALLURGY AND CERAMICS; ARGON; CARBON; CEMENTS; CONFIGURATION; CONVECTION; CRACKS; CREEP; DEFORMATION; DENSITY; DIAGRAMS; DIFFERENTIAL EQUATIONS; EFFICIENCY; ELASTICITY; EXTRUSION; FREQUENCY; GASES; GRAPHITE; HIGH TEMPERATURE; HYSTERESIS; INERT GASES; LABORATORY EQUIPMENT; MATHEMATICS; MEASURED VALUES; MIXING; POISSON EQUATIONS; ROTATION; SHEAR; STRESSES; SURFACES; TEMPERATURE; TENSILE PROPERTIES; THERMAL CONDUCTIVITY; THERMODYNAMICS; TORSION; ULTRASONICS; VACUUM; VELOCITY

Citation Formats

Mrozowski, S., Andrew, J.F., Repetski, J., Strauss, H.E., and Wobschall, D.C.. INVESTIGATION OF ELASTIC AND THERMAL PROPERTIES OF CARBON-BASE BODIES. United States: N. p., 1958. Web.
Mrozowski, S., Andrew, J.F., Repetski, J., Strauss, H.E., & Wobschall, D.C.. INVESTIGATION OF ELASTIC AND THERMAL PROPERTIES OF CARBON-BASE BODIES. United States.
Mrozowski, S., Andrew, J.F., Repetski, J., Strauss, H.E., and Wobschall, D.C.. Mon . "INVESTIGATION OF ELASTIC AND THERMAL PROPERTIES OF CARBON-BASE BODIES". United States. doi:.
@article{osti_4278067,
title = {INVESTIGATION OF ELASTIC AND THERMAL PROPERTIES OF CARBON-BASE BODIES},
author = {Mrozowski, S. and Andrew, J.F. and Repetski, J. and Strauss, H.E. and Wobschall, D.C.},
abstractNote = {Results are presented of a first year of a program designied to study the elastic and the conductive properties of toe carbon-base materials. A high precision apparatus for study of flexure and torsion deformations at room temperature with dependence on iime and the applied stress was developed, and complete stress-strain hysteresis type curves obtained. Prescnce of creep and permanent set both increasing in proportion to the logarithm of timc has been established. Furthermore, it has been found that the presence of the original extruded surface contributes to ihc shear but not to the Young's modulus. Noises originating from formation of cracks during the firsi deformation were listened to in an effort to undersiand the nature of creep and permanent set under these conditions. A direct determination of Poisson ratio for compression along ihe extrusion axis gave a result delta = 0.14 the J-57 engin 0.02. The velocity of ultrasonic waves has been found to depend strongly on the density of the graphite, but not on the frequency of the waves. An apparatus for the study of heat conductivity at high tempratures (1200 to 3000 C) was;onstructed and operated with either an argon atmosphere or under evaeuated eonditions. A number of representative types of carbon materials (soft and hard carbons, and mixed composites)s has been studieds and it was shown that the conductivity mainly depends on the particle type and less on the binder type used in ihe mix. Convection of gas contained in pores contributes to the measured over-all conductivity. No particle size dependence could be found. (auth)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 30 00:00:00 EDT 1958},
month = {Mon Jun 30 00:00:00 EDT 1958}
}

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  • The elastic properties and permanent set were investigated at room temperature for carbons made of graphitized filler and for carbons impregnated in the baked or graphitized state in dependence on the heat-treatment temperature. An apparatus for study of deformation at 1000 to 3000 deg C was built and calibrated and the first results for the variation of Young's modulus with ambient temperature were reported. Further studies of corrections to the heat conductivity from convection by gas across the pores were made and it is shown that such corrections are necessary even in the case of quite dense carbons. Transverse heatmore » diffusivity was investigated at 700 to 2800 deg C by a transient state method, using a newly constructed apparatus; good fit with the previously found data in the low temperature range is obtained. (auth)« less
  • In continuation of the work on elastic properties of carbons, using the greatly improved high temperature equipment, families of curves of the dependence of Young's modulus on temperature and on the heat treatment were obtained for four basic types of carbons and as far as possible, for a number of special types of commercial carbons. The amplitude dependence of internal friction and dynamic Young's modulus were investigated in the sonic range for a number of types of carbons as made and also neutron irradiated, as well as the temperature dependence of internal friction of the resonance frequency from room downmore » to liquid hydrogen temperature. The presence of a Bordoni peak at 50 deg K was found to be connected with the relaxation of motion of dislocations. Families of curves of the dependence of heat conductivity and electric resistivity on temperature and on the heat treatment were obtained for four basic types of carbons, using an improved technique. The steady'' sinusoidal wave technique for determination of heat diffusivity was improved in precision and extended in temperature range and data collected for several types of graphitized materials. (auth)« less
  • In continuation of the work four basic types of carbon were prepared, namely from 1) soft filler and soft binder, 2) soft filler and hard binder, 3) hard filler and soft binder, 4) hard filler and hard binder. Elastic moduli, permanent set, shrinkage and density; electric resistivity and thermal expansion coefficient were investigated in dependence on heat treatinent temperature and also the variation of the heat conductivity and electrical resistivity on ambient temperature in the range 1200 to 3000 deg C. An apparatus for direct determination of the heat diffusivity in the temperature range 100 to 700 deg C wasmore » set up and reasonably good data for the diffusivity coefficient obtained. Studies of ultra-attenuation show that the decay in intensity of transmitted waves is due to: 1) energy losses due to hysteresis effect present for all wavelengths, 2) scatter of waves by pores, observable only when the wavelength becomes shorter than 10 particle diameters. A discussion of the merits of various types of carbons closes the report. (auth)« less
  • Families of curves of the dependence of Young's modulus on temperature and on heat treatment were obtained for four basic types of carbons, using high temperature equipment. The decisive influence of filler type was established. As a result of gained experience, improvements in the associated electronics were introduced. The amplitude dependence of the internal friction and dynamic Young's modulus were, for the first time, investigated at room temperature for vibrations in the sonic range of frequencies for several types of carbons. Reproducibility was achieved in measurements of thermal conductivity with the new high temperature test apparatus and families of curvesmore » of the dependence of the conductivity on temperature and on heat treatment obtained for soft carbon. A new technique of determining the heat conductivity of carbons without internal heat generation was tried and found to work up to 1800 deg C. Improved results were obtained with the transient state technique of determination of the heat diffusivity by using a new fast responding pyrometer and a new improved apparatus for the steady sinusoidal wave technique constructed. (auth)« less
  • Research described in Appendix I conducted under Contracts AF33(616)- 5158; AF33(616)-6143; and AT(33-3)-4. Experimental data regarding the behavior and properties of a wide variety of binders are summarized. It is concluded that the high coke density of furfuryl alcohol (with toluene p-sulfonic acid), coal tar pitch, phenol formaldehyde, and phenol benzaldehyde are worthy of further investigation. A particular problem with the synthetic thermosetting resins is their narrow temperature range of gas evolution in dense structures. Continued work on fabrication techniques demonstrated the need for precise temperature control for molding pitch-bonded specimens, a vacuum enclosure for the mold, and a holdingmore » period during molding sufficient to insure temperature equillbrium. Combining these techniques limits variations in green density to less than plus or minus 0.0l gm/cc when 10% or more of thermax is substituted for coke flour. The influence of thermax additions to pitch-bonded coke is summarized and correlated with packing theory. Nearly a thousand specimens of pitchor furfuryl alcohol-bonded coke and coke-thermax have been made and carbonized for graphitization in a single batch. Specimens include 1 x 2 x 1/4-inches, 1 x 1 x 4inches, and 2.3 x 2.3-inches of thickness up to nearly two inches. Difficulties in obtaining sound structure have not been serious except with high-density furfuryl alcohol-bonded coke thermax or the largest specimens. Graphttized densities in excess of 1.8 gm/cc were achieved. Techniques for measuring flexural and tensile strength and flexural dynamic modulus of small specimens at room temperature to the creep threshold were developed and will be applied to experimental graphites. These measurements were applied to a molded commercial graphite (Speer No. 3499) and are appended in summary form. Differential thermograms for the most promising binders were obtained in several atmospheres at increased and reduced pressure. The reactions believed to influence the thermograms are confirmed by shrinkage domains (determined by dilatometry) at the same temperature levels. (auth)« less