Effect of Nd Addition on the Microstructure and Martensitic Transformation of Ni-Ti Shape Memory Alloys

Abstract

The effect of rare earth element Nd addition on the microstructure and martensitic transformation behavior of Ni 50 Ti 50− x Nd x (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>x</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0</mml:mn></mml:math>, 1, 3, 7, 20) shape memory alloy was investigated experimentally. The results showed that the microstructure of Ni-Ti-Nd ternary alloy consists of the NiNd phase and the NiTi matrix. One-step martensitic transformation was observed in all alloys. The martensitic transformation start temperature<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>increased gradually with increasing Nd content for Ni-Ti-Nd alloys.