Evaluation of damage evolution and material behavior in a sigma/Ti-6242 composite using nondestructive methods

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:566529

Benson, D; Karpur, P; Stubbs, D A; Matikas, T E ^[1]

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1. Univ. of Dayton, OH (United States). Research Inst.

Correlations between damage, as it evolves under simulated service conditions, and the results produced from nondestructive evaluation (NDE) techniques are useful in establishing successful life prediction methodologies in metal-matrix composites. Traditional characterization techniques provide limited information on the failure mechanisms in metal-matrix composites because of the complexities caused by the inhomogeneous, anisotropic nature of these materials. In addition, the currently used destructive techniques yield only qualitative information on the internal damage of composites. Very little quantitative information exists correlating the internal damage with property changes in the material such as stiffness, elongation, and residual strength. This research effort correlated NDE results with the residual tensile strength of a six-ply, unidirectional BP Sigma-1240 SiC/Ti-6Al-2Sn-4Zr-2Mo composite after being isothermally fatigued. Information obtained from these tests was used to pinpoint load levels and interruption points for subsequent interrupted fatigue tests. The following nondestructive evaluation techniques were used to evaluate the test specimens before and after fatigue testing: (1) scanning acoustic microscopy, (2) oblique incidence shear wave scanning, (3) reflector plate ultrasonic scanning, (4) immersion surface wave scanning, (5) in situ surface and longitudinal waves and, (6) X-ray radiography. This paper presents the results from each of the NDE techniques and examines the correlation among the techniques, other destructive methods, and the residual tensile strength.

• OSTI ID: 566529
• Report Number(s): CONF-950569--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CORRELATIONS
DAMAGE
MECHANICAL TESTS
NONDESTRUCTIVE TESTING
SERVICE LIFE
TENSILE PROPERTIES
THERMAL FATIGUE