【国外标准】 Standard Test Method for Uniaxial Constant Force Thermal Cycling of Shape Memory Alloys

5.1 Constant force thermal cycling tests determine the effect of stress on the transformation temperatures, recovered strain and residual strain of a shape memory alloy. The tests may be for one thermal cycle. A standard test method for force controlled repeated thermal cycling of shape memory alloys is currently under development.5.2 Measurement of the specimen's thermomechanical behavior closely parallels many shape memory applications and provides a result that is applicable to the function of the material.5.3 This test method may be used for, but is not limited to, wire, round tube, or strip samples. Thus it is able to provide an assessment of the product in its semi-finished form.5.4 This test method provides a simple method for determining transformation temperatures by heating and cooling specimens through their full thermal transformation under force.5.5 This test method can be used on trained and processed material in a semi-finished form to measure Two Way Shape Memory Effect by comparing the strain in the austenite state and martensite states with no minimal applied stress. The force is set to a minimum value not to exceed a corresponding stress of 7 MPa (in accordance Test Method F2516).5.6 This test method is useful for quality control, specification acceptance, and research.5.7 Transformation temperatures derived from this test method may not agree with those obtained by other test methods due to the effects of strain and stress on the transformation.5.8 Components such as springs or other semi-finished parts can be tested using this method as agreed upon by the customer and supplier. Units of stress and strain can be replaced with force and displacement.1.1 This test method defines procedures for thermomechanical cycling of shape memory alloy (SMA) material and components under constant force. This method characterizes the transformation properties such as transformation temperatures, actuation strain and residual strain, when a SMA is thermally cycled through the phase transformation under a constant applied force. This test is done to provide data for the selection of SMA materials, quality control, design allowables and actuator design.1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.