Scope:

ASTM F417 determines flexural strength or modulus of rupture of electronic grade ceramics. Modulus of Rupture is a measure of a specimen’s strength before rupture. The data is used by manufacturers in the quality control and selection process of Electronic-Grade Ceramics.

Test Procedure:

The two most common types of flexure tests are three-point and four-point flexural bending tests. The three-point bend test consists of the sample placed horizontally upon two points and the force applied to the top of the sample through a single point so that the sample is bent in the shape of a “V”.

A four-point bend test is roughly the same except that instead of the force applied through a single point on top it is applied through two points so that the sample experiences contact at four different points and is bent more in the shape of a “U”.

The three-point flexure test is ideal for the testing of a specific location of the sample, whereas, the four-point flexure test is more suited towards the testing of a large section of the sample, which highlights the defects of the sample better than a 3-point bending test.

 Specimen size:

This test method applies to specimens prepared from ceramic blanks with dimensions of at least 0.080 by 0.080 by 1 1/8 in. (2.0 by 2.0 by 28.6 mm).

Data:

Modulus of rupture

For circular specimen:

M = 8PL/πd3

For rectangular specimen:

M = 3 PL/2bd2

Where:
M = modulus of rupture
P = load at rupture
L = distance between supports
d = diameter of specimen