ASTM C1469 Test for Shear Strength of Joints of Advanced Ceramics

Scope:

A shear test provides information about the strength and deformation of materials under shear stresses. ASTM C1469 involves the shear test of joints in Advanced ceramics.

Joints enhance the performance and applicability of materials. The joints between similar materials are used for making complex parts and repairing components. The joints between dissimilar materials are used to capitalize on the unique properties of each constituent in the new component.

Under shear loading, joints require reasonable strength. Often joints are the weakest part of the component, therefore, it is important to know the strength of the joints under shear forces. Shear strength data is important in the development of joining techniques. It is used in material development, material comparison, quality assurance, characterization, and design data generation.

ASTM C1469 is used for joints with either low or intermediate strengths compared to the substrate material it joins. Joints with high strengths are not tested with this method because of the high probability of invalid test results due to fractures at the reaction points rather than in the joint.

Test Procedure:

ASTM C1469 is an asymmetrical four-point flexure test. The important apparatuses are Data Acquisition Device, Dimension-Measuring Devices, and Test Fixture. A test fixture holds the test specimen during the test. 
The thickness and width of the gauge section of the test specimen are measured. The test mode and test rate are selected on the test machine. The specimen is mounted on the fixture. The data acquisition and test mode are initiated. Load is applied and the specimen is fractured. The action of the test machine is disabled. The data collection is disabled. The breaking load is measured and recorded. The specimen is carefully removed and checked. The ASTM C1469 test is valid only if the fracture occurred in the joint.

 Specimen size:

The test specimen geometry depends on joint flexural strength. If the joint strength is low (less than 25% of the strength of the base material), the geometry of the joint is uniform. If the joint strength is moderate (25 to 50% of the strength of the base material), the geometry of the joint is straight or V-notched. If the joint strength is high (more than 50% of the strength of the base material), the material is not tested with ASTM C1469.

The width of the joint varies between 0.05 and 0.20 mm, based on the joining method used. 

Data:

Joint Shear Strength calculation for ASTM C1469:

Shear strength=P_max(S₀– S_i)/A (S₀ + S_I)

P_max = the breaking force in units of N,
S₀ and S_i = the outer and inner spans, respectively,
A = the shear area

where A = HB

H = the test specimen height, and
B = the test specimen width

Conclusion:

ASTM C1469 is used to determine the shear strength of joints in advanced ceramics at ambient temperature.