Effect of ternary alloying elements on the shape memory behavior of Ti–Ta alloys

• Published in: Acta materialia Vol. 57; no. 8; pp. 2509 - 2515
• Main Authors: Buenconsejo, Pio John S., Kim, Hee Young, Miyazaki, Shuichi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2009; Elsevier
• Subjects: Aging; Applied sciences; Exact sciences and technology; Metals. Metallurgy; Shape memory alloy; Ti–Ta; β Phase; ω Phase; Aging; Shape memory alloy; Ti–Ta; ω Phase; β Phase; Ti-Ta; Ageing; Composition effect; Alloying element
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2009.02.007

The effect of ternary alloying elements (X = V, Cr, Fe, Zr, Hf, Mo, Sn, Al) on the shape memory behavior of Ti–30Ta–X alloys was investigated. All the alloying elements decreased the martensitic transformation temperatures. The decrease in the martensitic transformation start ( M s) temperature due to alloying was affected by the atomic size and number of valence electrons of the alloying element. A larger number of valence electrons and a smaller atomic radius of an alloying element decreased the M s more strongly. The effect of the alloying elements on suppressing the aging effect on the shape memory behavior was also investigated. It was found that the additions of Sn and Al to Ti–Ta were effective in suppressing the effect of aging on the shape memory behavior, since they strongly suppress the formation of ω phase during aging treatment. For this reason the Ti–30Ta–1Al and Ti–30Ta–1Sn alloys exhibited a stable high-temperature shape memory effect during thermal cycling.