We offer multiple test methods to determine the temperatures at which phase transitions occur in our heat responsive shape memory alloys.
Differential Scanning Calorimetry (DSC) measures the change in energy as a function of temperature. As the test specimen is subjected to a thermal scan ranging from -150°C to 150°C, the endothermic and exothermic reactions are observed as the material changes phases. DSC analysis is critical in characterizing grades of binary NiTiNOL and quality control of all varieties of NiTiNOL. A small shift in Ni content can influence the austenitic transformation temperatures drastically, in turn affecting the performance of a part in the intended environment. Testing is performed in accordance to ASTM F2004.
Bend and Free Recovery (BFR) testing monitors the displacement of a wire sample or shape-set device as temperature is gradually increased. The wire or device is placed in a cool bath, approximately -55°C, and deformed when acclimated to the cold. As the temperature of the bath is gently heated, the device will then return to the original heat-set shape. The Active Af is then determined by plotting displacement data as a function of temperature. We have multiple testers to measure Active Af. A non-contact vision system measures the displacement in relation to fixed location indicators. The vision system is recommended for smaller wire samples, ≤0.6mm diameter. Our LVDT (Linear Variable Displacement Transducer) system measures displacement using a contact, counterbalanced probe. The LVDT system is recommended for shape-set devices, flat samples (sheet and ribbon) as well as larger wires, 0.6mm to 1.8mm diameter. Both test methods are in accordance to ASTM F2082.
Please contact us for more information regarding requests for custom thermal analysis testing.