Residual strain gradient determination in metal matrix composites by synchrotron X-ray energy dispersive diffraction

Journal Article · Sat May 01 00:00:00 EDT 1993 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02657242· OSTI ID:6350079

Kuntz, T A ^[1]; Wadley, H N.G. ^[2]; Black, D R ^[3]

---

1. APTECH Engineering Services, Inc., Sunnyvale, CA (United States)
2. Univ. of Virginia, Charlottesville (United States)
3. National Inst. of Standard and Tech., Gaithersburg, MD (United States)

An X-ray technique for the measurement of internal residual strain gradients near the continuous reinforcements of metal matrix composites has been investigated. The technique utilizes high intensity white X-ray radiation from a synchrotron radiation source to obtain energy spectra from small (10[sup [minus]3] mm[sup 3]) volumes deep within composite samples. The energy peak positions satisfy Bragg's law and allow determination of the lattice parameter. As the probe volume is translated, the peaks of the spectra shift and are used to infer lattice spacing changes and thus strains with a precision of 10[sup [minus]3] to 10[sup [minus]4] (depending on the sample grain size/probe volume ratio). The viability of the technique has first been tested using a model system with 800 [mu]m Al[sub 2]O[sub 3] fibers and a commercial purity titanium matrix. For this system (which remained elastic on cooling), good agreement was observed between the measured residual radial and hoop strain gradients and those estimated from a simple elastic concentric cylinders model. The technique was then used to assess the strains near (SCS-6) silicon carbide fibers in a Ti-14Al-21Nb matrix after consolidation processing. Reasonable agreement between measured and calculated strains was seen provided the probe volume was located 50 [mu]m or more from the fiber/matrix interface. Close to the interface, the measured elastic strains were smaller than anticipated, due to relaxation of the residual stress by plasticity and radial cracking during sample cooling.

• OSTI ID: 6350079
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Vol. 24:5; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
RESIDUAL STRESSES
ALUMINIUM OXIDES
COMPOSITE MATERIALS
NIOBIUM ALLOYS
SILICON CARBIDES
TITANIUM
TITANIUM BASE ALLOYS
CRACK PROPAGATION
ELASTICITY
FIBERS
GRAIN SIZE
INTERFACES
MATERIALS TESTING
MATRIX MATERIALS
PLASTICITY
REINFORCED MATERIALS
STRAINS
X-RAY SPECTROSCOPY
ALLOYS
ALUMINIUM COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
ELEMENTS
MATERIALS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SIZE
SPECTROSCOPY
STRESSES
TENSILE PROPERTIES
TESTING
TITANIUM ALLOYS
TRANSITION ELEMENTS
360603* - Materials- Properties