Effect of temperature on recovery stresses and properties of iron-based shape memory alloys
In order to study the effect of temperature on the recovery stress and mechanical properties of iron-based shape memory alloys(Fe-SMA),experiments on the temperature-related mechanical properties of Fe-SMA and their influence laws were carried out.Firstly,the effects of different activation temperatures on the recovery stress of Fe-SMA rods were investigated by pre-stretching and activation experiments,and an empiri-cal ontological model of recovery stress-temperature of Fe-SMA was established on the basis of experimental studies.Secondly,secondary heating experiments were carried out to investigate the effects of different activa-tion temperatures,additional loads,and exposure temperatures on the recovery stress of Fe-SMA rods.Finally,the mechanical properties of Fe-SMA rods after high temperature were investigated by monotonic tensile experi-ments.The results show that the established model of Fe-SMA recovery stress-temperature can effectively sim-ulate the relationship between recovery stress and temperature of Fe-SMA.During the secondary heating process,when the activation temperature is lower than 200 ℃,Fe-SMA has a high stress retention ratio,and the stress loss of Fe-SMA rods increases with the elevated of the additional load and the exposure temperature.After experiencing high temperature,the residual shape memory effect induces higher stresses in Fe-SMA rods compared to the initial stresses.The modulus of elasticity and ultimate strength exhibit relative stability,whereas the yield strength experiences a slight increase with rising exposure temperatures.This investigation serves as a reference for informing the fire-resistant design and utilization of Fe-SMA members in academic dis-course.
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