Apparent modulus of elasticity of near-equiatomic NiTi

Influence of Dynamic Compression on Phase Transformation of Martensitic NiTi Shape Memory Alloys

“…Within Stage I, samples deform linear-elastically as strain increases up~0.5 pct strain for both quasi-static and dynamic compression. While both samples exhibited an elastic modulus of about 32 GPa which is within the range of elastic moduli values reported in the literature, [15,52,55] there does appear to be some slight deviation from linearity in the dynamic compression curve in Stage I. After about 0.8 pct, the onset of the stress plateau was observed (Stage II), where the stress in the specimen increases less prominently with increasing strain.…”

“…pct Ti, which is consistent with Ti 2 Ni or Ti 4 Ni 2 O x particles, the later phase being more likely since it is more stable when forming an oxide. [42,52] Most of these particles are located at or near grain boundaries. After electropolishing for 2 minutes using 20 pct (by volume) H 2 SO 4 and 80 pct (by volume) CH 3 OH as an electrolyte, it can be seen that aligned martensitic twins are present in each grain and vary in direction depending on the specific grain orientation (as shown in Figure 2(b)).…”

Various stages in stress–strain curve of Ti–Al–Nb alloys undergoing SIMT

“…1 denote these stages during deformation. Several investigations [1,[5][6][7][8][9][10][11][12][13][14] have been carried out to clarify the nature of each stage in Ni-Ti and the results of these studies are summarized in the following. Stage 1 is the initial linear elastic region.…”

“…Stage 1 is the initial linear elastic region. In this stage, the parent phase undergoes an elastic deformation [5,6]. Stage 2 or stress plateau region corresponds to stress-induced transformation of metastable parent phase to martensite or reorientation of martensite present in initial microstructure [1,5,7].…”

“…In this stage, the parent phase undergoes an elastic deformation [5,6]. Stage 2 or stress plateau region corresponds to stress-induced transformation of metastable parent phase to martensite or reorientation of martensite present in initial microstructure [1,5,7]. In case the reorientation of martensite is responsible for deformation strain, the stress plateau is flat, but, when stress-induced martensite contributes to deformation strain, this stage is reported to exhibit gradual increase in stress with increase in strain [8] resulting in a rising stress plateau.…”