Development of Low-Cost Titanium-Manganese Shape Memory Alloys

Abstract:

Ti alloys are attractive materials for such applications, they are expensive due to the costly alloying elements such as Nb or Mo. The present authors have adopted Mn as a low-cost alloying element, and melted Ti-7, 7.5 and 8 mass%Mn-1.5 and 3mass%Al alloys using a laboratory-scale arc furnace. All specimens prepared from bottom ingots were heat treated at 1223 K for 3.6 ks and quenched in ice water. In the 7 and 7.5Mn-Al alloys, the β phase and orthorhombic martensite were identified using X-ray diffraction. In the 8Mn-Al alloys, only the β phase was identified. In the 7, 7.5, and 8Mn-Al alloys, the electrical resistivity at room and liquid nitrogen temperature increased with increasing Al content due to dissolution of Al into the β phase, whereas the Vickers hardness decreased with increasing Al content due to decreasing formation of athermal omega by the addition of Al. Heat treatment at 673 K for 60 s almost completely returned deformed Ti-7 and 7.5Mn-3Al specimens to their original shapes, and heat treatment at 773 K for 60 s almost returned deformed Ti-8Mn-Al specimens to their original shapes.

• Periodical: Materials Science Forum (Volume 941)
• Pages: 1254-1259
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.1254
• Online since: December 2018
• Authors: Masahiko Ikeda*, Masato Ueda
• Keywords: Beta-Phase, Electrical Resistivity, Orthorhombic Martensite, Shape Recovery, Vickers Hardness

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