Low-alloy content Ti-Mo-based alloys with large superelasticity and narrow stress hysteresis for potential biomedical applications

Figures & data

Table 1. Nominal and actual chemical compositions of the studied Ti-8Mo-6Zr-6Sn-(0–5)Al (wt%) alloys.

	Nominal	Actual composition (wt%)
Alloy	composition (wt%)	Mo	Zr	Sn	Al	O	Ti
0Al	Ti-8Mo-6Zr-6Sn	6.91	5.35	5.57	–	0.065	Bal.
1Al	Ti-8Mo-6Zr-6Sn-1Al	6.95	5.46	5.56	1.09	0.066	Bal.
2Al	Ti-8Mo-6Zr-6Sn-2Al	7.37	5.88	5.96	2.27	0.069	Bal.
3Al	Ti-8Mo-6Zr-6Sn-3Al	7.28	5.68	5.79	3.24	0.068	Bal.
4Al	Ti-8Mo-6Zr-6Sn-4Al	7.54	5.92	5.91	3.93	0.070	Bal.
5Al	Ti-8Mo-6Zr-6Sn-5Al	7.76	5.88	6.16	4.59	0.078	Bal.

Figure 1. XRD patterns (a), DSC curves (b) and loading-unlading stress-strain curves (c) of the TMZSA specimens solid-solution treated at 900°C for 30 min. The red dashed lines with arrows below the stress-strain curves in (c) represent the recovery strain due to the shape memory effect.

Figure 2. Comparison maps of stress hysteresis ($\Delta {\sigma }_{\mathrm{hys}}$) vs ${\sigma }_{\text{β}\to {\alpha }^{″}}$ (a) and stress hysteresis ($\Delta {\sigma }_{\mathrm{hys}}$) vs alloying element content (b) of 4Al and 5Al alloy specimens in the present study and other typical superelastic Ni-free Ti-Nb-, Ti-Zr(-Hf)- and Ti-Mo-based shape memory alloys subjected to solid-solution treatment (ST), annealing (AN) or aging treatment (AG) [2–4,11,14,16–39]. The ${\sigma }_{\text{β}\to {\alpha }^{″}}$ represents the critical stress for inducing β → α″ martensitic transformation. Alloy compositions in at% in alloys are converted to wt% in (b) for comparison. The red arrows in (a) represent the desired properties of narrow stress hysteresis and high yield strength (${\sigma }_{\text{β}\to {\alpha }^{″}}$) and those in (b) represent the desired alloys with low content of alloying elements and narrow stress hysteresis.

Figure 3. Cyclic loading-unloading stress-strain curves obtained at room temperature of the 4Al (a) and 5Al (b) alloy specimens solid-solution treated at 900°C for 30 min. The applied strain of the first cycle is set as 1.5% and is increased by 0.5% in each following cycle. (c) The plot of recovery strain (${ϵ}_r$) as a function of the applied strain of 4Al and 5Al alloy specimens in the present study and other typical superelastic Ni-free Ti-Mo-based shape memory alloys subjected to solid-solution treatment (ST), annealing (AN) or aging treatment (AG) [4,5,16–18,38,39].

Table 2. Comparison of ${\sigma }_{\text{β}\to {\alpha }^{″}}$, $\Delta {\sigma }_{\mathrm{hys}}$ and ${ϵ}_r^{\max }$ measured by cyclic loading-unloading tensile tests of Ti-8Mo-6Zr-6Sn-(4, 5)Al and typical superelastic Ni-free Ti-Nb, Ti-Zr and Ti-Mo-based shape memory alloys subjected to solid-solution treatment or aging treatment for biomedical applications.

	${\sigma }_{\text{β}\to {\alpha }^{″}}$	$\Delta {\sigma }_{\mathrm{hys}}$	${ϵ}_r^{\max }$
Alloy	(MPa)	(MPa)	(%)	Ref.
Ti-8Mo-6Zr-6Sn-5Al (wt%)	477	117	4.4	This study
Ti-8Mo-6Zr-6Sn-4Al (wt%)	443	256	4.3	This study
Ti-15Nb-3Mo-1.25Sn (at%)	271	121	3.7	[2]
Ti-15Nb-3Mo-1.5Sn (at%)	344	78	2.1	[2]
Ti-3Mo-7Sn-3Zr (at%)	245	190	5.1	[3]
Ti-8Mo-13Sn (wt%)	509	252	3.1	[4]
Ti-18Zr-13.5Nb-3Al (at%)	220	120	6.1	[14]
Ti-5Mo-5Sn (at%)	500	260	3.5	[16,17]
Ti-6Mo-4Sn (at%)	525	320	4.0	[18]
Ti-18Zr-11Nb-3Sn (at%)	330	130	6.0	[19]
Ti-24Zr-10Nb-2Sn (at%)	310	160	7.0	[21]
Ti-18Zr-4.5Nb-3Sn-2Mo (at%)	250	150	6.2	[22]
(Ti-Zr)−1.5Mo-3Sn (at%)	340	180	7.0	[25]
Ti-40Zr-8Nb-2Sn (at%)	360	220	5.5	[26]
Ti-9.8Mo-3.9Nb-2V-3.1Al (wt%)	520	360	3.4	[39]

Figure 4. Selected-area diffraction patterns and the corresponding dark-field TEM images taken by the circled diffraction spots for the 4Al (a, a-1) and 5Al (b, b-1) alloy specimens solid-solution treated at 900°C for 30 min.

Figure 5. A schematic diagram showing the Al content dependence of ${\sigma }_{\text{β}\to {\alpha }^{″}}$: (a) β matrix without ${\omega }_{\mathrm{ath}}$, (b) β matrix with ${\omega }_{\mathrm{ath}}$ adapted from Refs. [2,9].

Kim HY, Fu J, Tobe H, et al. Crystal structure, transformation strain, and superelastic property of Ti-Nb-Zr and Ti-Nb-Ta alloys. Shap Mem Superelasticity. 2015;1:107–116. doi:10.1007/s40830-015-0022-3

 Google Scholar

Kim HY, Nakai K, Fu J, et al. Effect of Al on superelastic properties of Ti-Zr-Nb-based alloys. Funct Mater Lett. 2017;10:1740002. doi:10.1142/S1793604717400021

 Web of Science ®Google Scholar

Li S, Kim JH, Kang SW, et al. Superelastic metastable Ti-Mo-Sn alloys with high elastic admissible strain for potential bio-implant applications. J Mater Sci Tech. 2023;163:45–58. doi:10.1016/j.jmst.2023.01.061

 Web of Science ®Google Scholar

Wang CH, Liu M, Hu PF, et al. The effects of α″ and ω phases on the superelasticity and shape memory effect of binary Ti-Mo alloys. J Alloy Compd. 2017;720:488–496. doi:10.1016/j.jallcom.2017.05.299

 Web of Science ®Google Scholar

Cai S, Daymond MR, Ren Y, et al. Influence of short time anneal on recoverable strain of beta III titanium alloy. Mater Sci Eng A. 2013;562:172–179. doi:10.1016/j.msea.2012.11.005

 Web of Science ®Google Scholar

Song J, Zhang X, Fan Z, et al. Mechanical deformation and tensile super-elastic behaviors of a Ti-Mo based shape memory alloy. Proceedings Volume 7977, Active and Passive Smart Structures and Integrated Systems, 2011; SPIE. p. 869–878. doi:10.1117/12.881851

 Google Scholar

Ijaz MF, Kim HY, Hosoda H, et al. Effect of Sn addition on stress hysteresis and superelastic properties of a Ti-15Nb-3Mo alloy. Scr Mater 2014;72–73:29–32. doi:10.1016/j.scriptamat.2013.10.007

 Web of Science ®Google Scholar

Endoh K, Tahara M, Inamura T, et al. Effect of Sn and Zr content on superelastic properties of Ti-Mo-Sn-Zr biomedical alloys. Mater Sci Eng A. 2017;704:72–76. doi:10.1016/j.msea.2017.07.097

 Web of Science ®Google Scholar

Maeshima T, Ushimaru S, Yamauchi K, et al. Effect of heat treatment on shape memory effect and superelasticity in Ti-Mo-Sn alloys. Mater Sci Eng A. 2006;438–440:844–847. doi:10.1016/j.msea.2006.05.092

 Web of Science ®Google Scholar

Maeshima T, Ushimaru S, Yamauchi K, et al. Effects of Sn content and aging conditions on superelasticity in biomedical Ti-Mo-Sn alloys. Mater Trans. 2006;47:513–517. doi:10.2320/matertrans.47.513

 Web of Science ®Google Scholar

Sutou Y, Yamauchi K, Takagi T, et al. Mechanical properties of Ti-6at.% Mo-4at.% Sn alloy wires and their application to medical guidewire. Mater Sci Eng A. 2006;438–440:1097–1100. doi:10.1016/j.msea.2006.01.116

 Web of Science ®Google Scholar

Fu J, Yamamoto A, Kim HY, et al. Novel Ti-base superelastic alloys with large recovery strain and excellent biocompatibility. Acta Biomater. 2015;17:56–67. doi:10.1016/j.actbio.2015.02.001

 PubMed Web of Science ®Google Scholar

Pavόn LL, Kim HY, Hosoda H, et al. Effect of Nb content and heat treatment temperature on superelastic properties of Ti-24Zr-(8–12)Nb-2Sn alloys. Scr Mater. 2015;95:46–49. doi:10.1016/j.scriptamat.2014.09.029

 Web of Science ®Google Scholar

Fu J, Kim HY, Miyazaki S. Effect of annealing temperature on microstructure and superelastic properties of a Ti-18Zr-4.5Nb-3Sn-2Mo alloy. J Mech Behav Biomed Mater. 2017;65:716–723. doi:10.1016/j.jmbbm.2016.09.036

 PubMed Web of Science ®Google Scholar

Ijaz MF, Kim HY, Hosoda H, et al. Superelastic properties of biomedical (Ti-Zr)-Mo-Sn alloys. Mater Sci Eng C. 2015;48:11–20. doi:10.1016/j.msec.2014.11.010

 PubMed Web of Science ®Google Scholar

Li S, Nam TH. Superelasticity and tensile strength of Ti-Zr-Nb-Sn alloys with high Zr content for biomedical applications. Intermetallics. 2019;112:106545. doi:10.1016/j.intermet.2019.106545

 Web of Science ®Google Scholar

Nohira N, Chiu WT, Umise A, et al. Achievement of room temperature superelasticity in Ti-Mo-Al alloy system via manipulation of ω phase stability. Materials (Basel). 2022;15:861. doi:10.3390/ma15030861

 PubMed Web of Science ®Google Scholar