Effects of Niobium Addition on Fe-30Mn-6Si-5Cr Shape Memory Alloys
Date Issued
2015
Date
2015
Author(s)
Chen, Yee-Jei
Abstract
In this study, Fe-30Mn-6Si-5Cr, Fe-30Mn-6Si-5Cr-0.1Nb, Fe-30Mn-6Si-5Cr-0.5Nb and Fe-30Mn-6Si-5Cr-1.0Nb shape memory alloys were prepared using the vacuum arc re-melting (VAR) technique. The Fe-30Mn-6Si-5Cr-0.5Nb alloy, which exhibits the best shape memory performance among these alloys, was then subjected to the thermo-mechanical treatments and shape memory training. The adding of 0.5wt% Nb followed by ageing at 700°C for 2 hours could make the recovery ratio rise up to 90.83%. The Fe-30Mn-6Si-5Cr-0.5Nb alloy, which exhibits the best shape memory performance, is then subjected to the shape memory training. The recovery ratios increase with increasing training cycles. The shape recovery ratio reaches ~100% in the fifth training cycle. Cold-working has been applied to Fe-30Mn-6Si-5Cr-0.5Nb alloy to fabricate the pre-strained 5% and 10% samples. The pre-strained 5% sample with aging at 700°C for 2 hours could exhibit a best shape recovery ratio. The Fe-30Mn-6Si-5Cr-0.5Nb alloy with a 5% pre-straining and 700°C aging was subjected to the shape memory training. The recovery ratio increases with increasing training cycles. After four training cycles, the recovery ratio is nearly 100%.
Subjects
Fe-Mn-Si-Cr shape memory alloys
shape memory effect
niobium
shape memory training
Type
thesis
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