ASTM C1421-09

1.1 These test methods cover the fracture toughness, K_Ic, determination of advanced ceramics at ambient temperature. The methods determine K_Ipb (precracked beam test specimen), K_Isc (surface crack in flexure), and K_Ivb (chevron-notched beam test specimen). The fracture toughness values are determined using beam test specimens with a sharp crack. The crack is either a straight-through crack formed via bridge flexure (pb), or a semi-elliptical surface crack formed via Knoop indentation (sc), or it is formed and propagated in a chevron notch (vb), as shown in Fig. 1.

Note 1 - The terms bend(ing) and flexure are synonymous in these test methods.

1.2 These test methods are applicable to materials with either flat or with rising R-curves. Differences in test procedure and analysis may cause the values from each test method to be different. For many materials, such as the silicon nitride Standard Reference Material 2100, the three methods give identical results at room temperature in ambient air.

1.3 The fracture toughness values for a material can be functions of environment, test rate and temperature. These test methods give fracture toughness values for specific conditions of environment, test rate and temperature.

1.4 These test methods are intended primarily for use with advanced ceramics which are macroscopically homogeneous. Certain whisker- or particle-reinforced ceramics may also meet the macroscopic behavior assumptions. Single crystals may also be tested.

1.5 This standard begins with a main body that provides information on fracture toughness testing in general. It is followed by annexes and appendices with specific information for the particular test methods.

Main Body	Section
Scope	1
Referenced Documents	2
Terminology (including definitions, orientation and symbols)	3
Summary of Test Methods	4
Significance and Use	5
Interferences	6
Apparatus	7
Test Specimen Configurations, Dimensions and Preparations	8
General Procedures	9
Report (including reporting tables)	11
Precision and Bias	12
Keywords	13
Summary of Changes
Annexes
Test Fixture Geometries	A1
Procedures and Special Requirements for Precracked Beam Method	A2
Procedures and Special Requirements for Surface Crack in Flexure Method	A3
Procedures and Special Requirements for Chevron Notch Flexure Method	A4
Appendices
Precrack Characterization, Surface Crack in Flexure Method	X1
Complications in Interpreting Surface Crack in Flexure Precracks	X2
Alternative Precracking Procedure, Surface Crack in Flexure Method	X3
Chamfer Correction Factors, Surface Crack in Flexure Method Only	X4
Crack Orientation	X5

Product Details

Published:

05/01/2009

Number of Pages:

32

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1 file , 910 KB

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2 files , 1.7 MB

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Document History

ASTM C1421-18

ASTM C1421-16

ASTM C1421-15

ASTM C1421-10

ASTM C1421-09

ASTM C1421-01b(2007)

ASTM C1421-01a

ASTM C1421-01b