ASTM E3098 Mechanical Uniaxial Pre-strain and Thermal Recovery of Shape Memory Alloys

Scope:

ASTM E3098 test method covers the shape memory effect properties of the specimen. The stiffness of the material, recovery of the deformed portion, strain calculation, functioning, product assessment, transformation temperatures, quality control, specification acceptance, and research are dealt with in this method. This creates ease for the customer and supplier to reach an agreement. Moreover, the values of stress and strain are determined, and compensation and recovery techniques are applied.

Procedure:

In ASTM E3098, a test apparatus, such as a compression testing machine with blocks and strain transducer, is used. The temperature regulators are installed to detect the continuous shift of temperature. The test specimen is cooled to its martensitic state and deformed under the uniaxial loading. The force is removed, and the specimen is heated and cooled continuously to measure its extension and contraction against the specimen temperature. The specific strain rates are determined, and stress is applied to equilibrate the temperature and strain. The time, strain, stress, and temperature are recorded throughout the process.

Specimen size

For ASTM E3098 testing, the specimen size should be as per the requirements. In this case, the length of the specimen should be a minimum of 1 times the diameter.

Data:

Temperature is maintained at ±3 °C while heating and cooling the specimen. The strain at upper cycle temperature (e_UCT)and strain at lower cycle temperature (e_LCT) is determined respectively.

Conclusion:

ASTM E3098 test method covers the shape memory effect properties of the specimen.