D. Jiang, Y. Yan, J. Jiang, China University of Petroleum, Beijing, Beijing, China; L. Cui, Y. Zheng, X. Jiang, China University of Petroleum, Beijing, China
The temperature memory effect (TME) in Ti50Ni15Nb35 and Ti48Ni17Nb35 alloys was investigated by using differential scanning calorimeter (DSC). After several incomplete thermal cycles upon heating to the arrest temperature, the TME appeared in the next 30 complete thermal cycles. This is contradictive to the previous understanding, that is, TME could be erased totally by one complete thermal cycle. In our research, we also found that the numbers of the incomplete thermal cycle plays an important role in inducing this repeatable TME. However, with increasing of heating rate, the memory effect became weaker and disappeared within fewer cycling numbers. These were considered closely relating to the existence of a large number of interfaces between the TiNiNb and (Nb, Ti) phases.
Summary: In this work, the temperature memory effect (TME) in Ti50Ni15Nb35 and Ti48Ni17Nb35 alloys was studied. After several incomplete thermal cycles upon heating to the arrest temperature, the TME appeared in the next 30 complete thermal cycles. The alloy without incomplete thermal cycle training could also memory the arrest temperature several times, though it was not as many times as the training one. This is contradictive to the previous understanding, that is, TME could be erased totally by one complete thermal cycle. N points of temperatures could be memorized if N times of incomplete cycles on heating were performed with different arrested temperatures in a decreasing order. With increasing of heating rate, the memory effect became weaker and disappeared within fewer cycling numbers. These were considered closely relating to the existence of a large number of interfaces between the TiNiNb and (Nb, Ti).
