VAMAS TWA #3
Project #7: Fractography Round Robin
Organized by: U. S. Army Research Laboratory, (Mr. Swab) and National Institute of Standards
and Technology, (Mr. Quinn), 1993.
Objective
Determine whether fractographers can find and characterize fracture origins in strength-test specimens.
How should origins be characterized? Are the interpretations consistent?
Determine whether a MIL Handbook on fractographic analysis was useful, and whether
participants could recommend improvements.
Approach
| Topic 1: | Machining Damage Interpretation, Photo analysis (each lab, 18 photos) |
| Topic 2: | Fracture Origin Characterization, Specimen examination (each lab, 6 specimens)
Specimen examination. Each lab received
6 specimens with different origin types |
| Topic 3: | Characterization of Participant's Own Materials |
Outcome
Round Robin Completed in 1994. 19 Laboratories participated.
(USA 8; UK 2; Germany 3; France 1; CEC 1; Belgium 1; Switzerland 1; Sweden 1, Japan 0)
Principal Findings
- The general approach of the MIL HDBK was acceptable, but it had some gaps and areas
that needed improvement.
- Fractographers are like detectives. They must integrate all the "clues" and information to
analyze a fracture origin.
- Fractographers should use fracture mechanics more often to aid interpretation. The MIL
HDBK was inadequate in this regard.
- There is a shortage of fracture mirror constants for today's ceramics. Guidelines for how
to measure mirror constants should be developed.
Standards Impact
ASTM Standard Practice for Fractographic Analysis, C 1322-96 was adapted from MIL HDBK 790
after the lessons of this round robin were incorporated.
A CEN Committee TC 184 draft is under development.
Publications
- J. Swab and G. Quinn, "Results of a Round Robin Exercise on the Fractography of Advanced
Structural Ceramics," Ceram. Eng. and Sci. Proc., Vol. 15, #5, 1994, pp. 867-876.
- J. Swab and G. Quinn, "Fractography of Advanced Structural Ceramics," to be publ. in
Proceeding of the Conference on "Advanced Materials and Process Technology for Mechanical
Failure Prevention," April, 1994.
- J. J. Swab and G. D. Quinn, "Fractography and Characterization of Fracture Origins in
Advanced Ceramics, A VAMAS Round Robin," pp. 569-576 in New Horizons for Materials,
Proceedings of the 8th World Ceramic Congress, CIMTEC, Florence, Italy, ed P. Vincenzini,
Techna, Faenza, 1995.
- J. Swab and G. Quinn, "Fractography of Advanced Structural Ceramics: Results from Topic #2
of the VAMAS Round Robin Exercise," Ceram. Eng. and Sci. Proc., Vol. 16, No. 5 (1995), pp.
929-938.
- J. Swab and G. Quinn, "Fractography of Advanced Structural Ceramics: Results from the
VAMAS Round Robin Exercise," U. S. Army Technical Report, ARL TR-656, Dec. 1994.
Also Published as VAMAS Technical Report #19.
- J. J. Swab and G. D. Quinn, "The VAMAS Fractography Round Robin: A Piece of the
Fractography Puzzle," Ceramic Transactions, Vol. 64, American Ceramic Society, Westerville,
OH, 1996.
- G. D. Quinn and J. J. Swab, "Fractography and Estimates of Fracture Origin Size from Fracture Mechanics,"
Ceram. Eng. and Sci. Proc., 17 [3] (1996) pp. 51 -58
In addition, NIST created a Website which incorporates fractographic elements and lessons learned from this VAMAS round robin:
http://www.ceramics.nist.gov/webbook/fracture/fracture.htm
For more information or copies of the reports, contact:
Mr. Jeffrey Swab, Weapons and Materials Directorate, Aberdeen Proving Ground, Aberdeen, MD 21005,Tel: 410 306 0753,
email: jswab@arl.mil,
or
Mr. George Quinn, NIST Ceramics Division, Gaithersburg, MD 20899, USA, Tel: (+001) 301 975 5765,
email: geoq@nist.gov
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