ASTM C1327-15
Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics

Standard No.

ASTM C1327-15

Release Date

2015

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM C1327-15(2019)

Latest

ASTM C1327-15(2019)

Scope

5.1 For advanced ceramics, Vickers indenters are used to create indentations whose surface-projected diagonals are measured with optical microscopes. The Vickers indenter creates a square impression from which two surface-projected diagonal lengths are measured. Vickers hardness is calculated from the ratio of the applied force to the area of contact of the four faces of the undeformed indenter. (In contrast, Knoop indenters are also used to measure hardness, but Knoop hardness is calculated from the ratio of the applied force to the projected area on the specimen surface.)

5.2 Vickers indentation hardness is one of many properties that is used to characterize advanced ceramics. Attempts have been made to relate Vickers indentation hardness to other hardness scales, but no generally accepted methods are available. Such conversions are limited in scope and should be used with caution, except for special cases where a reliable basis for the conversion has been obtained by comparison tests.

5.3 Vickers indentation diagonal lengths are approximately 2.8 times shorter than the long diagonal of Knoop indentations, and the indentation depth is approximately 1.5 times deeper than Knoop indentations made at the same force.

5.4 Vickers indentations are influenced less by specimen surface flatness, parallelism, and surface finish than Knoop indentations, but these parameters must be considered nonetheless.

5.5 Vickers indentations are much more likely to cause cracks in advanced ceramics than Knoop indentations. The cracks may influence the measured hardness by fundamentally altering the deformation processes that contribute to the formation of an impression, and they may impair or preclude measurement of the diagonal lengths due to excessive damage at the indentation tips or sides.

5.6 A full hardness characterization includes measurements over a broad range of indentation forces. Vickers hardness of ceramics usually decreases with increasing indentation size or indentation force, as shown in Fig. 1. The trend is known as the indentation size effect (ISE). Hardness approaches a plateau constant hardness at sufficiently large indentation size or forces. The test forces or loads that are needed to achieve a constant hardness vary with the ceramic. The test force specified in this standard is intended to be sufficiently large that hardness is either close to or on the plateau, but not so large as to introduce excessive cracking. A comprehensive characterization of the ISE is recommended but is beyond the scope of this test method, which measures hardness at a single, designated force.

1.1 This test method covers the determination of the Vickers indentation hardness of advanced ceramics. In this test, a pointed, square base, pyramidal diamond indenter of prescribed shape is pressed into the surface of a ceramic with a predetermined force to produce a relatively small, permanent indentation. The surface projection of the two diagonals of the permanent indentation is measured using a light microscope. The average diagonal size and the applied force are used to calculate the Vickers hardness, which represents the material’s resistance to penetration by the Vickers indenter......

ASTM C1327-15 Referenced Document

• ASTM E177 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E384 Standard Test Method for Microindentation Hardness of Materials
• ASTM E4 Standard Practices for Force Verification of Testing Machines
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• IEEE/ASTM SI 10 American National Standard for Metric Practice
• ISO 6507 Metallic materials - Vickers hardness test - Part 4: Tables of hardness values
• JIS R 1610 Test methods for hardness of fine ceramics

ASTM C1327-15 history

• 2019 ASTM C1327-15(2019) Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics
• 2015 ASTM C1327-15 Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics
• 2008 ASTM C1327-08 Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics
• 2003 ASTM C1327-03 Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics
• 1999 ASTM C1327-99 Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics