The effect of thermal training on prestrained Fe-30Mn-6Si-5Cr shape memory alloy

Comparative study on the effect of samarium additions on thermo-mechanical behaviour of shape memory alloys

“…The maximum value of c/a ratio (1.704) is obtained at the samarium contents of 0.64% and the calculated increase in c/a ratio is about 5% when it is compared with the alloy having no samarium. It is pertinent to mention here that our calculated values of c/a ratio and lattice constants are very close to the measured values reported in the literature [39][40][41].…”

“…It can be noticed that the presence of ά is confirmed only in alloy sample 4. The presence of ά is usually considered to be detrimental for the shape memory behaviour because it retards the reverse transformation of (e) and transform directly into austenite [37,39,40,43]. The distortion of lattice by foreign solute atoms has been confirmed by our results presented in Table 1.…”

“…The improvement in shape memory effect of alloy samples (1 and 4) during initial training cycles can be regarded as the effect of reduction in the values of proof stress and critical stress which facilitates the formation of stress induced martensite (e). The degradation of shape memory effect of alloy samples (1 and 4) after attaining its maximum shape memory effect with further training cycles is because of softening of alloys (reduction in proof stress) during training which encourages the formation of multi variant stacking faults, their intersection and ά (bcc martensite) [24,28,32,37,[39][40][41][42]. Figure 9 shows the scanning electron images of alloy samples (1 and 4) after inducing 3% strain and six training cycles.…”

Improvement of shape memory effect in Fe–Mn–Si alloy by slight tantalum addition

“…In the past decades, extensive studies of the Fe-Mn-Si-based alloys focused on the improvement of their shape memory performance by means of composition design [2][3][4][5][6], thermo-mechanical training [6][7][8][9][10][11][12][13], and precipitation strengthening [14][15][16][17], etc. The thermo-mechanical training has proven to be the most effective way to improve the shape memory performance, but it may lead to increase in the production cost and difficulties involved in the fabrication of complex shapes.…”

The stress relaxation of a Fe59Mn30Si6Cr5 shape memory alloy

“…Their SME arises from the reverse transformation of stressinduced martensite (HCP structure) into ␥ parent austenite (fcc structure) upon heating [1]. In the past decade, extensive studies of the Fe-Mn-Si-Cr alloys were made focusing on the transformation behavior [1,[7][8][9], physical properties [7][8][9][10], effects of thermo-mechanical training [11][12][13][14] and composition dependence of SME and corrosion resistance [5,[15][16][17][18][19][20][21]. Also, effort is made to increase the use of these alloys, especially the "heatto-shrink" pipe coupling [22].…”