Heating rate effects on reverse martensitic transformation in a Cu – Zn – Al shape memory alloy

2011 ◽  
Vol 102 (11) ◽  
pp. 1345-1351 ◽  
Author(s):  
Nicoleta Monica Lohan ◽  
Bogdan Pricop ◽  
Leandru-Gheorghe Bujoreanu ◽  
Nicanor Cimpoeşu
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Heating Rate ◽  
Reverse Martensitic Transformation ◽  
Rate Effects

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.

The Constrained Stress-Induced ε Reverse Martensitic Transformation Characteristic of Fe-Mn-Si Alloy Embedded in Cement Matrix

2010 ◽  
Vol 44-47 ◽  
pp. 2229-2233 ◽  
Author(s):  
Lin Lin Liu ◽  
Cheng Xin Lin ◽  
Chao Yu Zhou
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Reverse Transformation ◽  
Cement Matrix ◽  
X Ray Diffraction ◽  
Temperature Zone ◽  
Alloy Wire ◽  
Reverse Martensitic Transformation ◽  
X Ray

The constrained stress-induced ε reverse martensitic transformation characteristic of Fe-17Mn-5Si-10Cr-5Ni shape memory alloy wire embedded in cement matrix was studied by X-Ray Diffraction (XRD) and metallographical. The results show that the finish temperature (Af) of the constrained reverse transformation of Fe-17Mn-5Si-10Cr-5Ni shape memory alloy in cement matrix, compared with the unconstrained alloy, is elevated. With increasing the pre-strain, the Af is higher, and reverse transformation temperature zone is broadened. The main result which causes martensitic reverse transformation harder is that Fe-Mn-Si alloy deformation coordination is limited by cement matrix constrained.

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