TY - JOUR

T1 - Influence of Detwinning on the Shape Memory Effect in Ni55Fe18Ga27 Single Crystals

AU - Belyaev, Sergey

AU - Resnina, Natalia

AU - Nikolaev, Vladimir

AU - Timashov, Roman

AU - Saveleva, Anastasiya

AU - Gazizullina, Aigul

AU - Krymov, Vladimir

AU - Sibirev, Alexey

PY - 2019/7/15

Y1 - 2019/7/15

N2 - Deformation mechanisms, one-way and two-way shape memory effects were studied in the mode of compression in the [011] single crystal of the Ni55Fe18Ga27 alloy where the detwinning occurred during deformation and in the [001] single crystal where the detwinning was forbidden. It was found that the [001] and [011] crystals deformed by different mechanisms during compression to 5% (reorientation was in [001] crystal, and the reorientation and detwinning were in [011] crystal) and from 15 to 20% (the 14 M → L10 transition was in [001] crystal and plastic deformation of 14 M phase was in [011]). The compression of both single crystals from 5 to 15% occurred due to the same mechanisms: the 10 M ↔ 14 M transformation and the plastic deformation of the 14 M martensite. The 14 M and L10 phases were stable under load, and they transformed to the 10 M martensite on unloading. It was shown that the crystal orientation and detwinning hardly affected the value of the one-way shape memory effect since both crystals were in the 10 M martensite after preliminary deformation. In this case, the transformation of 10 M martensite to the austenite on heating was accompanied by a strain of about 5% and this was the maximum value of the shape memory effect. It was found that the detwinning significantly affected the temperature ranges of strain recovery. In the [011] crystal, the strain recovered in a very narrow interval on heating (1-2°C), whereas in the [001] crystal the shape memory effect was observed in “normal” temperature range (~ 10°C). The detwinning resulted in the formation of a large oriented internal stress during the preliminary deformation that increased the value of the two-way shape memory effect that was observed in [011] crystals in comparison with the [001] crystals.

AB - Deformation mechanisms, one-way and two-way shape memory effects were studied in the mode of compression in the [011] single crystal of the Ni55Fe18Ga27 alloy where the detwinning occurred during deformation and in the [001] single crystal where the detwinning was forbidden. It was found that the [001] and [011] crystals deformed by different mechanisms during compression to 5% (reorientation was in [001] crystal, and the reorientation and detwinning were in [011] crystal) and from 15 to 20% (the 14 M → L10 transition was in [001] crystal and plastic deformation of 14 M phase was in [011]). The compression of both single crystals from 5 to 15% occurred due to the same mechanisms: the 10 M ↔ 14 M transformation and the plastic deformation of the 14 M martensite. The 14 M and L10 phases were stable under load, and they transformed to the 10 M martensite on unloading. It was shown that the crystal orientation and detwinning hardly affected the value of the one-way shape memory effect since both crystals were in the 10 M martensite after preliminary deformation. In this case, the transformation of 10 M martensite to the austenite on heating was accompanied by a strain of about 5% and this was the maximum value of the shape memory effect. It was found that the detwinning significantly affected the temperature ranges of strain recovery. In the [011] crystal, the strain recovered in a very narrow interval on heating (1-2°C), whereas in the [001] crystal the shape memory effect was observed in “normal” temperature range (~ 10°C). The detwinning resulted in the formation of a large oriented internal stress during the preliminary deformation that increased the value of the two-way shape memory effect that was observed in [011] crystals in comparison with the [001] crystals.

KW - advanced characterization

KW - deformation mechanisms

KW - detwinning

KW - intermetallics

KW - mechanical

KW - shape memory effects

KW - single crystal

KW - NIFEGA ALLOYS

KW - HIGH-TEMPERATURE SUPERELASTICITY

KW - DEFORMATION

KW - MARTENSITIC TRANSFORMATIONS

KW - RECOVERY

KW - BURST CHARACTER

KW - NI

KW - TRANSITIONS

UR - http://www.scopus.com/inward/record.url?scp=85068847933&partnerID=8YFLogxK

U2 - 10.1007/s11665-019-04188-8

DO - 10.1007/s11665-019-04188-8

M3 - Article

AN - SCOPUS:85068847933

VL - 28

SP - 4234

EP - 4240

JO - Journal of Materials Engineering and Performance

JF - Journal of Materials Engineering and Performance

SN - 1059-9495

IS - 7

ER -