chapter 9 fracture testing. (a) charpy impact testing machine. (b) charpy impact test specimen. (c)...
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Chapter 9Fracture Testing
(a) Charpy impacttesting machine. (b) Charpy impacttest specimen. (c) Izod impact testspecimen.
Impact TestingImpact TestingCharpy Impact Testing
Energy absorbed versustemperature for a steel in annealedand in quenched and temperedstates. (Adapted with permissionfrom J. C. Miguez Suarez and K. K.Chawla, Metalurgia-ABM, 34 (1978)825.)
Energy Absorbed vs. Temperature
Effect of temperatureon the morphology of fracturesurface of Charpy steel specimen.Test temperatures Ta < Tb < Tc <Td. (a) Fully brittle fracture. (b, c)Mixed-mode fractures. (d) Fullyductile (fibrous) fracture.
Temperature Effect on Fracture Surface
Results of Charpy testsfor AISI 1018 steel (cold drawn).
Charpy Testing of Steel: DBTT
Drop-weight testspecimen.
Drop-Weight Test Specimen
Charpy V-notch curvefor a pressure-vessel steel. Notethat the NDT temperaturedetermined by the drop-weighttest corresponds to the high-toughregion of the Charpy curve.Pneumatic pressurization; material:21/4 Cr-1 Mo steel, yield stress590 MPa. (After W. J. Langford,Can. Met. Quart., 19 (1980) 13.)
Charpy V-notch Curve
(a) Typical oscilloscoperecord of an instrumented Charpyimpact test. (b) Schematicrepresentation of (a).
Oscilloscope Record
Typical ASTM standardplane-strain fracture toughnesstest specimens. (a) Compacttension. (b) Bending. (c)Photograph of specimens ofvarious sizes. Charpy and tensilespecimens are also shown, forcomparison purposes. (Courtesyof MPA, Stuttgart.)
Fracture Toughness Test Specimens
Schematic of typicalload–displacement curves in a KIctest.
Load Displacement Curves vs. Fracture Toughness Test
Plastic zone at the x1crack tip in a plate of finitethickness.
Plastic Zone at Crack Tip
Assembly formeasuring displacement in anotched specimen.
Displacement Measurement
Measuring Conditioned Value KQ
Variation in Kc withflaw size, specimen thickness, andspecimen width.
Variation of Kc with Specimen Thicckness
Load P vs. Crack Opening Displacement: Different Responses
“Plastic hinge” mechanism of deformation.
Plastic Hinge Mechanism
Method fordetermining JIc. (a) Load identicalspecimens to differentdisplacements. (b) Measure theaverage crack extension by heattinting. (c) Calculate J for eachspecimen. (d) Plot J versus a tofind JIc.
J-Integral Testing
Normal stresses alonga section of beam for linearlyelastic material.
Flexure Test
Application of loadsand bending moment diagrams for(a) three-point bending and (b)four-point bending tests.
Three-Point and Four-Point Bend (Flexure) Tests
TThree-Point
Shematic drawing ofthe miniaturized disk-bend test.(Adapted from H. Li, F. C. Chen,and A. J. Ardell, Met. Trans A, 22(1991) 2061.)
Miniaturized Specimen:Four-Point Bending
Fracture-testingmethods for brittle materials. (a)Double-cantilever beam (DCB). (b)Double torsion. (c) Notch flexure.
Fracture Testing Methods for Ceramics
Chevron notch test.(a) Schematic of the testarrangement and the details of thenotch plane. (b) The chevron tiplength, a0, can be measured fromoptical micrographs of brokenspecimens. (c) Chevron short-rodspecimen.
Chevron Notch Test
Fractures produced byhardness indentations in (a) AsS3glass (courtesy of B. R. Lawn andB. J. Hockey) and (b) Al203.
Hardness Indentation in Brittle Materials
Schematicrepresentation of indentationgenerating a plastic deformationregion and a semicircular crack.
Plastic Deformation and Crack in Indentation of Brittle Material
Comparison betweenconventional and indentationfracture toughness determinationsfor glasses and ceramics. (From G.R. Anstis, P. Chankitul, B. R. Lawn,and D. B. Marshall, J. Am. Cer. Soc.,64 (1981) 533.)
Fracture Toughness: Comparison by Different test Methods
Indentation tests forthe determination of toughness ofbond between substrate and thinfilm; (a) method used for ductilecoating on brittle substrate (typicalof electronic components); (b)method used for brittle coatingson ductile substrate; (c) calculatednormalized energy release rate asa function of normalized crackdiameter. (Adapted from J. J.Vlassak, M. D. Drory, and W. D.Nix, J. Mater. Res., 12 (1997) 100.)
Adhesion of Thin Film to Substrate: Testing