Fig. 1 Room temperature XRD patterns of (Ti-V-Al)100-xSnx shape memory alloys

Fig. 2 Dependence of average valence electrons on Sn contents in (Ti-V-Al)100-xSnx shape memory alloys

Fig. 3 a Lattice parameters and b lattice volume of (Ti-V-Al)100-xSnx shape memory alloys with the different Sn contents

Fig. 4 Optical images of solution-treated (Ti-V-Al)100-xSnx shape memory alloys: a x = 0.5; b x = 1.0; c x = 3.0; d x = 5.0

Fig. 5 Effect of Sn content on the grain size of solution-treated (Ti-V-Al)100-xSnx shape memory alloys

Fig. 6 Bright field TEM images and corresponding SAED patterns of (Ti-V-Al)100-xSnx shape memory alloys: a, b x = 1.0; c, d x = 3.0

Fig. 7 $\overline{Bo }-\overline{Md }$ diagrams in (Ti-V-Al)100-xSnx shape memory alloys

Fig. 8 DSC curves of the solution-treated Ti-V-Al shape memory alloys with different Sn contents: a 0.5 at.%; b 1.0 at.%; c 3.0 at.%; d 5.0 at.%

Fig. 9 Variation of staring temperature of reverse martensitic transformation (As) with a Mo Eq., b the number of valence electrons per atom (e/a) and c Cv d contour views of the curve As vs Mo Eq., e/a and Cv

Fig. 10 a Tensile stress-strain curves of (Ti-V-Al)100-xSnx shape memory alloys at room temperature; b influence of Sn content on fracture strength, yield strength and elongation of (Ti-V-Al)100-xSnx shape memory alloys; c relationship between the yield stress and temperature in shape memory alloys

Fig. 11 A comparison of mechanical properties of Ti-V-Al-based shape memory alloys

Fig. 12 Fracture surface images of (Ti-V-Al)100-xSnx shape memory alloys: a x = 0.5; b x = 1.0; c x = 3.0; d x = 5.0

Fig. 13 Effect of Sn content on micro-hardness of (Ti-V-Al)100-xSnx shape memory alloys (the insets represent the morphology of micro-hardness trace)

Fig. 14 a Strain recovery characteristics of Ti-V-Al-based shape memory alloys; b influence of Sn content on the strain recovery characteristics of Ti-V-Al-based shape memory alloys