scholarly journals Microstructural characterization of Cu82.3Al8.3Mn9.4 shape memory alloy after rolling

10.30544/314 ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 281-289
Author(s):  
Mirko Gojić ◽  
Stjepan Kožuh ◽  
Ivana Ivanić ◽  
Magdalena Selanec ◽  
Tamara Holjevac Grgurić ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Microstructural Characterization ◽  
Rolling Process ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Hot And Cold Rolling

In this paper, the microstructure of Cu82.3Al8.3Mn9.4 (in wt. %) shape memory alloy after hot and cold rolling was investigated. The Cu82.3Al8.3Mn9.4 alloy was produced by a vertical continuous casting method in the form a cylinder rod of 8 mm in diameter. After the casting, hot and cold rolling was performed. By hot rolling a strip with a thickness of 1.75 mm was obtained, while by cold rolling a strip with a thickness of 1.02 mm was produced. After the rolling process, heat treatment was performed. Heat treatment was carried out by solution annealing at 900 °C held for 30 minutes and water quenched immediately after heating. The microstructure characterization of the investigated alloy was carried out by optical microscopy (OM), scanning electron microscopy (SEM) equipped with a device for energy dispersive spectroscopy (EDS). Phase transformation temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC) method. The homogenous martensite microstructure was confirmed by OM and SEM micrographs after casting. During rolling the two-phase microstructure occurred. Results of DSC analysis showed martensite start (Ms), martensite finish (Mf), austenite start (As) and austenite finish (Af) temperatures.

Effect of Electroplastic Deformation on Martensitic Transformation in Coarse Grained and Ultrafine Grained Ni-Ti Shape Memory Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 127-132 ◽  
Author(s):  
Anastasia E. Sergeeva ◽  
Daria Setman ◽  
Michael Zehetbauer ◽  
Sergey Prokoshkin ◽  
Vladimir V. Stolyarov
Keyword(s):  
Differential Scanning Calorimetry ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Coarse Grained ◽  
Scanning Calorimetry ◽  
Structure Relaxation ◽  
Differential Scanning Calorimetry Method ◽  
Ultrafine Grained

The aim of this paper is the investigation of electroplastic deformation (EPD) and subsequent annealing influence on martensitic transformation in the shape memory Ni50.7Ti49.3 alloy. Using differential scanning calorimetry method it was shown that EPD at the low strain stimulates structure relaxation and recovers martensitic transformation in cooling, which is usually suppressed by cold rolling.

scholarly journals Microstructural characterization of NiTi shape memory alloy produced by rotary hot forging

2017 ◽  
Vol 32 (S1) ◽  
pp. S201-S206
Author(s):  
P. Rodrigues ◽  
F. M. Braz Fernandes ◽  
A. S. Paula ◽  
J. P. Oliveira ◽  
S. B. Ribeiro ◽  
...  
Keyword(s):  
Shape Memory ◽  
Thermomechanical Processing ◽  
Niti Alloy ◽  
Cold Deformation ◽  
Hot Forging ◽  
Microstructural Characterization ◽  
Niti Shape Memory Alloy ◽  
Scanning Calorimetry ◽  
Rotary Forging

The thermomechanical processing of NiTi shape memory alloys usually involves several steps of hot and/or cold deformation. The present work presents the structural characterization of a Ni-rich NiTi alloy bar, produced by vacuum-induced melting and thermomechanical processing in laboratory scale, aiming at massive production in the future. This study focused on the first step of hot working at 800 °C during rotary forging. Microstructural characterization was performed using differential scanning calorimetry, high- and low-temperature X-ray diffraction (XRD) using a laboratory source and synchrotron XRD. Thus, it was possible to obtain the phase transformation characteristics of the material: the transformation temperatures and the transformation sequence. Proposed thermomechanical processing is intended for production of bars and wires that will be subsequently drawn to get thin wires, for different applications, including orthodontic arch wires.

Microstructural characterization of Ni-Mn-Ga ferromagnetic shape memory alloy powders

2004 ◽  
Vol 95 (11) ◽  
pp. 6954-6956 ◽  
Author(s):  
Virgil C. Solomon ◽  
David J. Smith ◽  
YunJun Tang ◽  
Ami E. Berkowitz
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Microstructural Characterization ◽  
Ferromagnetic Shape Memory Alloy ◽  
Ferromagnetic Shape Memory

High Damping Capacity of a Binary TiNi Shape Memory Alloy

2011 ◽  
Vol 687 ◽  
pp. 485-489
Author(s):  
Zhi Shan Yuan ◽  
Zhao Wei Feng ◽  
Wei Dong Miao ◽  
Jiang Bo Wang ◽  
Jin Zhou ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Parent Phase ◽  
Damping Capacity ◽  
Quenching Rate ◽  
Scanning Calorimetry

TiNi shape memory alloys exhibiting high damping capacity are currently expected to be used as structural materials for energy dissipation or vibration control applications. In this paper, the characterization of damping behaviour of a binary TiNi SMA was performed by dynamic mechanical analyzer (DMA) instrument and differential scanning calorimetry (DSC) equipment. Damping tests measuring Tanδ, storage modulus E' and loss modulus E" of Ti49.2Ni50.8 binary shape memory alloy were investigated at different temperature, using different frequency and strain amplitude. It shows that quenching rate has a significant effect on the damping capacity of TiNi SMA by exhibiting different phase transformation behavior. Internal friction values (Q-1) corresponding to cubic B2 parent phase to rhombohedral R phase transformation, B2-R, and R-B19' monoclinic martensite transformation are as high as 0.177 and 0.078, respectively. The occurrence of R-phase significantly softens the storage modulus and thus promotes the damping capacity of TiNi SMAs.

INFLUENCES OF HEAT TREATMENT ON TRANSFORMATION BEHAVIORS OF NEAR-EQUIATOMIC POROUS NITI SHAPE MEMORY ALLOY

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2410-2416
Author(s):  
H. C. JIANG ◽  
Y. CHEN ◽  
S. W. LIU ◽  
L. J. RONG
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Niti Alloy ◽  
Niti Shape Memory Alloy ◽  
Scanning Calorimetry ◽  
Pore Characteristics ◽  
Transformation Temperatures ◽  
Porous Niti ◽  
High Temperature Synthesis

The pore characteristics and pore size distribution of porous near-equiatomic NiTi shape memory alloy fabricated by self-propagating high-temperature synthesis (SHS) are described in detail. The effects of different heat treatments on the transformation of porous NiTi alloy were investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that heat treatment had strong influences on the transformation temperatures and latent heats of transformation. When the porous alloy was annealed at 648K and 748K for 3.6ks, two steps transformation including R transformation occurred during cooling and heating and the R transformation temperatures are lower than B 2↔ B 19' transformation temperatures. However, no transformation was detected within the experimental temperature range if the porous alloy was solution treated at 1133K for 2.4ks. This novel phenomenon was the results of extensive Ti2Ni intermetallic compound precipitation. The transformation temperatures of porous NiTi alloy after annealing at 1323K for 3.6ks were much lower than those of the untreated alloy.

scholarly journals The influence of heat treatment on microstructure and phase transformation Temperatures of Cu-Al-Ni shape memory alloy

2019 ◽  
Vol 68 (3-4) ◽  
pp. 111-118 ◽  
Author(s):  
Ivana Ivanić ◽  
Mirko Gojić ◽  
Borut Kosec ◽  
Tamara Holjevac Grgurić ◽  
Stjepan Kožuh
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Microstructural Analysis ◽  
Solution Annealing ◽  
Scanning Calorimetry ◽  
Transformation Temperatures ◽  
Casting Technique ◽  
Before And After

This paper presents the results of thermal and microstructural analysis of Cu-Al-Ni shape memory alloy before and after heat treatment. After casting, a bar of Cu-12.8 Al-4.1 Ni (wt.%) alloy, obtained by the vertical continuous casting technique, was subjected to a certain heat treatment procedure. Solution annealing was performed at 850 °C for 60 min, followed by water quenching. Tempering was then performed at four different temperatures (150 °C, 200 °C, 250 °C and 300 °C). The microstructural results were obtained by optical and scanning electron microscopy. Thermodynamic calculation of ternary Cu-Al-Ni system under equilibrium was performed using Thermo-Calc 5 software. Phase transformation temperatures were determined by differential scanning calorimetry (DSC). The DSC results show the highest values of transformation temperatures in as-cast state. After solution annealing and tempering, the transformation temperatures show lower values with exceptional stability of Ms temperature (martensite start temperature).

Effect of Heat Treatment Temperature on the Mechanical Property in Cast TiNi Shape Memory Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 1493-1496
Author(s):  
Kazuhiro Kitamura ◽  
Yutaka Sawada ◽  
Toshio Kuchida ◽  
Tadashi Inaba ◽  
Masataka Tokuda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Tensile Test ◽  
Shape Memory ◽  
Treatment Temperature ◽  
Scanning Calorimetry ◽  
Temperature Synthesis ◽  
Treatment Conditions ◽  
High Temperature Synthesis

The heat treatment effect of a cast shape memory alloy (SMA) from self-propagating high temperature synthesis (SHS) ingot was investigated. The composition of SHS ingot was Ti-50.8at%Ni. DSC and Tensile test specimens were cast by lost-wax process from SHS ingot. The heat treatment conditions were 400°C-60min., 500°C-60min. and 600°C-60min. for DSC and 400°C-60min. and 500°C-60min. for tensile test. Transformation temperatures were measured by differential scanning calorimetry (DSC). Mechanical properties were measured by a tensile test at several temperatures. The effects of heat treatment temperatures were same as a general TiNi wire material.

Influence of Thermomechanical Treatment on Transformation Temperatures of Cu-Al-Ni Shape Memory Alloys

2008 ◽  
Vol 59 ◽  
pp. 92-100
Author(s):  
Ana Cris R. Veloso ◽  
Rodinei Medeiros Gomes ◽  
Dagoberto Brandao Santos ◽  
I.C.E.G. Lima ◽  
Severino Jackson Guedes de Lima ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Thermomechanical Treatment ◽  
Hot Rolling ◽  
Rolling Process ◽  
Induction Melting ◽  
Scanning Calorimetry ◽  
Transformation Temperatures

In this study Cu-13.8Al alloys with 3.0% and 4.0% (wt%) of nickel were obtained by induction melting. The effect of homogenization heat treatment and hot rolling on the transformation temperatures of these alloys was investigated by differential scanning calorimetry. It was observed that the transformation temperatures increase with long homogenization times, and also by hot rolling, and this displacement is smaller for alloys with 4.0% of nickel. In both alloys in the quenched state, the reversion reaction is characterized by the appearance of multiple peaks attributed to the presence of martensites 2H and 18R. The influence of the rolling process must be associated with the loss of Ni and Al during the process.

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