Effects of Niobium Addition on Fe-30Mn-6Si-5Cr Shape Memory Alloys

• Main Authors: Yee-Jei Chen, 陳怡潔
• Other Authors: Hsin-Chih Lin
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/37353799063512309281

碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 103 === 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%.