1. Chapter 9 Fracture Testing

2. Charpy Impact Testing Impact Testing Impact Testing (a) Charpy impact
testing machine. (b) Charpy impact
test specimen. (c) Izod impact test
specimen.

3. Energy Absorbed vs. Temperature
Energy absorbed versus
temperature for a steel in annealed
and in quenched and tempered
states. (Adapted with permission
from J. C. Miguez Suarez and K. K.
Chawla, Metalurgia-ABM, 34 (1978)‏
825.)‏

4. Temperature Effect on Fracture Surface
Effect of temperature
on the morphology of fracture
surface of Charpy steel specimen.
Test temperatures Ta < Tb < Tc <
Td. (a) Fully brittle fracture. (b, c)‏
Mixed-mode fractures. (d) Fully
ductile (fibrous) fracture.

5. Charpy Testing of Steel: DBTT
Results of Charpy tests
for AISI 1018 steel (cold drawn).

6. Drop-Weight Test Specimen

7. Charpy V-notch Curve Charpy V-notch curve
for a pressure-vessel steel. Note
that the NDT temperature
determined by the drop-weight
test corresponds to the high-tough
region of the Charpy curve.
Pneumatic pressurization; material:
21/4 Cr-1 Mo steel, yield stress
590 MPa. (After W. J. Langford,
Can. Met. Quart., 19 (1980) 13.)‏

8. Oscilloscope Record (a) Typical oscilloscope
record of an instrumented Charpy
impact test. (b) Schematic
representation of (a).

9. Fracture Toughness Test Specimens
Typical ASTM standard
plane-strain fracture toughness
test specimens. (a) Compact
tension. (b) Bending. (c)‏
Photograph of specimens of
various sizes. Charpy and tensile
specimens are also shown, for
comparison purposes. (Courtesy
of MPA, Stuttgart.)‏

10. Load Displacement Curves vs. Fracture Toughness Test
Schematic of typical
load–displacement curves in a KIc
test.

11. Plastic Zone at Crack Tip
Plastic zone at the x1
crack tip in a plate of finite
thickness.

12. Displacement Measurement
Assembly for
measuring displacement in a
notched specimen.

13. Measuring Conditioned Value KQ

15. Variation of Kc with Specimen Thicckness
Variation in Kc with
flaw size, specimen thickness, and
specimen width.

16. Load P vs. Crack Opening Displacement: Different Responses

17. Plastic Hinge Mechanism
mechanism of deformation.

18. J-Integral Testing Method for determining JIc. (a) Load identical
specimens to different
displacements. (b) Measure the
average crack extension by heat
tinting. (c) Calculate J for each
specimen. (d) Plot J versus a to
find JIc.

19. Flexure Test Normal stresses along a section of beam for linearly
elastic material.

20. Three-Point and Four-Point Bend (Flexure) Tests
TThree-Point
Application of loads
and bending moment diagrams for
(a) three-point bending and (b)‏
four-point bending tests.

21. Miniaturized Specimen:Four-Point Bending
Shematic drawing of
the miniaturized disk-bend test.
(Adapted from H. Li, F. C. Chen,
and A. J. Ardell, Met. Trans A, 22
(1991) 2061.)‏

22. Fracture Testing Methods for Ceramics
methods for brittle materials. (a)‏
Double-cantilever beam (DCB). (b)‏
Double torsion. (c) Notch flexure.

23. Chevron Notch Test Chevron notch test. (a) Schematic of the test
arrangement and the details of the
notch plane. (b) The chevron tip
length, a0, can be measured from
optical micrographs of broken
specimens. (c) Chevron short-rod
specimen.

24. Hardness Indentation in Brittle Materials
Fractures produced by
hardness indentations in (a) AsS3
glass (courtesy of B. R. Lawn and
B. J. Hockey) and (b) Al203.
Add equation

25. Plastic Deformation and Crack in Indentation of Brittle Material
Schematic
representation of indentation
generating a plastic deformation
region and a semicircular crack.

26. Fracture Toughness: Comparison by Different test Methods
Comparison between
conventional and indentation
fracture toughness determinations
for glasses and ceramics. (From G.
R. Anstis, P. Chankitul, B. R. Lawn,
and D. B. Marshall, J. Am. Cer. Soc.,
64 (1981) 533.)‏

27. Adhesion of Thin Film to Substrate: Testing
Indentation tests for
the determination of toughness of
bond between substrate and thin
film; (a) method used for ductile
coating on brittle substrate (typical
of electronic components); (b)‏
method used for brittle coatings
on ductile substrate; (c) calculated
normalized energy release rate as
a function of normalized crack
diameter. (Adapted from J. J.
Vlassak, M. D. Drory, and W. D.
Nix, J. Mater. Res., 12 (1997) 100.)‏