Effects of mechanical constraint on thermally induced reverse martensitic transformation in granular shape memory ceramic packings

2020 ◽  
Vol 128 (24) ◽  
pp. 245102
Author(s):  
Hunter A. Rauch ◽  
Hang Z. Yu
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Thermally Induced ◽  
Reverse Martensitic Transformation ◽  
Mechanical Constraint

Effect of L21 Ordering on the Martensitic and Intermartensitic Transformations in a Ni-Mn-Ga Shape Memory Alloy

2007 ◽  
Vol 130 ◽  
pp. 127-134
Author(s):  
Concepcio Seguí ◽  
Jaume Pons ◽  
Eduard Cesari
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Single Crystal ◽  
Shape Memory ◽  
Parent Phase ◽  
Heat Treatments ◽  
Free Energies ◽  
Transformation Temperatures ◽  
Reverse Martensitic Transformation ◽  
Order Degree

The present work analyses the influence of austenite ordering on a single crystal Ni-Mn- Ga alloy which displays, on cooling, a sequence of martensitic (MT) and intermartensitic (IMT) transformations. The MT and IMT show distinct behaviour after ageing in austenite: while the MT temperatures are not affected by the performed heat treatments, the IMT shifts toward lower temperatures after quenching from increasing temperatures, progressive recovery occurring upon ageing in parent phase. Such evolution can be related to changes in the L21 order degree, in the sense that ordering favours the occurrence of the intermartensitic transformation, while it does not affect noticeably the forward and reverse martensitic transformation temperatures. The closeness of the free energies of the different martensite structures allows to explain this behaviour.

scholarly journals Влияние предварительной сжимающей нагрузки на работу, производимую монокристаллами Cu-Al-Ni при взрывном восстановлении деформации памяти формы

2022 ◽  
Vol 48 (3) ◽  
pp. 44
Author(s):  
Р.Б. Тимашов ◽  
П.Н. Якушев ◽  
С.А. Пульнев ◽  
В.И. Николаев
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Single Crystals ◽  
Strain Recovery ◽  
Preliminary Deformation ◽  
Reverse Martensitic Transformation ◽  
The Impact ◽  
Dsc Calorimetry ◽  
Impact Mode

The ability of martensitic single crystals Cu 82.5 wt.% - Al 13.5 wt.% - Ni 4.0 to perform work has been investigated. It is shown that weight placed on the crystal is transferred smoothly or by impact during shape memory strain recovery (SMS) Moving depends on the preliminary deformation of the crystal. An influence of the preload on this work is studied. It was found that the transition to the impact mode occurs after preliminary compression of the crystal to the full SMS (~ 9%), when the load is more than twice the stress of the detwinning of martensite. DSC calorimetry showed that after compression to 200–250 MPa and higher sharp narrowing of reverse martensitic transformation (RMT) peak takes place.

Sign in / Sign up

Export Citation Format

Share Document