ASTM C1421-01b(2007)
Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature

Standard No.

ASTM C1421-01b(2007)

Release Date

2001

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM C1421-09

Latest

ASTM C1421-18

Scope

These test methods may be used for material development, material comparison, quality assessment, and characterization.

The pb and the vb fracture toughness values provide information on the fracture resistance of advanced ceramics containing large sharp cracks, while the sc fracture toughness value provides this information for small cracks comparable in size to natural fracture sources.

Note 48212;Cracks of different sizes may be used for the sc method. If the fracture toughness values vary as a function of the surface crack size it can be expected that K_Isc will differ from K_Ipb and K_Ivb.

1.1 These test methods cover the fracture toughness determination of KIpb (precracked beam test specimen), KIsc (surface crack in flexure), and KIvb (chevron-notched beam test specimen) of advanced ceramics at ambient temperature. The fracture toughness values are determined using beam test specimens with a sharp crack. The crack is either a straight-through crack (pb), or a semi-elliptical surface crack (sc), or it is propagated in a chevron notch (vb).

Note 1

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

1.2 These test methods determine fracture toughness values based on a force and crack length measurement (pb, sc), or a force measurement and an inferred crack length (vb). In general, the fracture toughness is determined from maximum force. Applied force and displacement or an alternative (for example, time) are recorded for the pb test specimen and vb test specimen.

1.3 These test methods are applicable to materials with either flat or with rising R-curves. The fracture toughness measured from stable crack extension may be different than that measured from unstable crack extension. This difference may be more pronounced for materials exhibiting a rising R-curve.

Note 2

One difference between the procedures in these test methods and test methods such as Test Method E 399, which measure fracture toughness, KIc, by one set of specific operational procedures, is that Test Method E 399 focuses on the start of crack extension from a fatigue precrack for metallic materials. In these test methods the test methods for advanced ceramics make use of either a sharp precrack formed via bridge flexure (pb) or via Knoop indent (sc) prior to the test, or a crack formed during the test (vb). Differences in test procedure and analysis may cause the values from each test method to be different. Therefore, fracture toughness values determined with these methods cannot be interchanged with KIc as defined in Test Method E 399 and may not be interchangeable with each other.

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

1.5 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.

1.6 These test methods are divided into three major parts and related sub parts as shown below. The first major part is the main body and provides general information on the test methods described, the applicability to materials comparison and qualification, and requirements and recommendations for fracture toughness testing. The second major part is composed of annexes that provide procedures, test specimen design, precracking, testing, and data analysis for each method. Annex A1 describes suggested test fixtures,......

ASTM C1421-01b(2007) history

• 2018 ASTM C1421-18 Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
• 2016 ASTM C1421-16 Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
• 2015 ASTM C1421-15 Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
• 2010 ASTM C1421-10 Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
• 2009 ASTM C1421-09 Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
• 2001 ASTM C1421-01b(2007) Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
• 2001 ASTM C1421-01b Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature
• 2001 ASTM C1421-01a Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperatures
• 2001 ASTM C1421-99 Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperatures