| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 100 === Fe-Mn-Si-Cr-based shape memory alloys have good workability, low price and advantages in the bonding of the sleeve element. With good shape memory Fe-Mn-Si-Cr-based alloys in this study, we try to add it with trace rhenium (Re) element. After different aging treatment, we go through the bending test and analysis of micro-structure, then we choose the one of the better shape memory effect to do heat treatment and shape memory training.
In Fe-30Mn-6Si-5Cr、Fe-30Mn-6Si-5Cr-0.05Re、Fe-30Mn-6Si-5Cr-0.1Re and Fe-30Mn-6Si-5Cr-0.3Re alloys, there will be BCC structure of the precipitated phase in the grain boundaries and the parent phase through aging above 600℃ for 2 hours. It is called phase which is similar to the parent phase. Afer aging at 700℃ for 2 hours, the alloys have the better hardness and shape memory recovery.
Apply cold-working on Fe-30Mn-6Si-5Cr-0.1Re alloy to make pre-strain 5%, 10%, 15% and 20%. The shape memory recovery will be better through the one of pre-strain 5% through aging at 700℃ for 2 hours. Use this one to do shape memory training experiment. The recovery rate will increase with training times. After 2 times, the recovery rate will almost be 100%. It is concluded that we can get the best shape memory alloy efficiently by using both heat treatment and shape memory training.
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