Influence of the Reprocessing by Plasma Melting and Injection Molding on the Thermomechanical Properties of a Ni-Ti SMA Manufactured by VIM

2014 ◽  
Vol 1611 ◽  
pp. 31-36 ◽  
Author(s):  
Jackson de Brito Simões ◽  
Francisco Fernando Roberto Pereira ◽  
Jorge Otubo ◽  
Carlos José de Araújo
Keyword(s):  
Injection Molding ◽  
Thermomechanical Properties ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Copper Mold ◽  
Scanning Calorimetry ◽  
Mechanical And Physical Properties ◽  
Different Shapes ◽  
Plasma Melting ◽  
Specific Limitation

ABSTRACTShape Memory Alloys (SMA) metallic materials that change their mechanical and physical properties with temperature variation and mechanical loading, surprising engineers and researchers. In this way, one can develop thermomechanical actuators capable, for example, of generating force by blocking the shape recovery or change the natural frequency of a mechanical system by blocking resonance. The processing of these SMA are countless, each one with its specific limitation and particularity. This study aims to evaluate the influence of rapid solidification of a Ni-Ti SMA that is originally manufactured by Vacuum Induction Melting (VIM) and reprocessed by Plasma Melting (PM) followed by injection molding into different metal molds (steel, brass, aluminum and copper). The influence of such a processing is analyzed through Differential Scanning Calorimetry (DSC) and Electrical Resistance as a function of Temperature (ERT) to determine the effects on transformation temperatures. The results demonstrate that by using the copper mold one can provide greater uniformity of the material properties. Thus, there is the possibility of obtaining different kinds of SMA mini-actuators by PM injection in a copper mold and that includes different shapes and sizes that can be studied further.

Study of a Cu-Al-Mn Shape Memory Alloy Produced by Plasma Melting Followed by Injection Molding

2014 ◽  
Vol 1611 ◽  
pp. 25-30
Author(s):  
Francisco Fernando Roberto Pereira ◽  
Maria Goretti Ferreira Coutinho ◽  
Bruno Moura Miranda ◽  
Carlos José de Araújo
Keyword(s):  
Injection Molding ◽  
Shape Memory ◽  
Shape Recovery ◽  
Permanent Deformation ◽  
Melting Process ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Dynamical Mechanical Analysis ◽  
Plasma Melting ◽  
New Applications

ABSTRACTShape Memory Alloys (SMA) are characterized by the capacity to recover a permanent deformation after being heated above a critical temperature called Final Austenite Temperature (Af). The Ni-Ti SMA are the most commercially used, however recent studies showed that the Cu-Al-Mn SMA present significant shape recovery and mechanical properties, showing a strong potential for developing new applications. In this context, the main goal of this work is to manufacture a Cu-Al-Mn SMA through a plasma melting process followed by injection molding of liquid metal and then characterize the samples, using the following techniques: Optical Microscopy (OM), Differential Scanning Calorimetry (DSC), Electrical Resistance as a function of Temperature (ERT) tests, Dynamical Mechanical Analysis (DMA) and Microhardness (MH).

scholarly journals Effect of Sn Addition on Phase Transformation Behavior of Equiatomic Ni-Ti Shape Memory Alloy

2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0961
Author(s):  
Ali Abadi Aljubouri ◽  
Safa hasan Mohammed ◽  
Mudhafar ali Mohammed
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Optical Microscope ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Micro Hardness ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
Phase Transformation Behavior

Sn effect on the phase transformation behavior, microstructure, and micro hardness of equiatomic Ni-Ti shape memory alloy was studied. NiTi and NiTiSn alloys were produced using vacuum induction melting process with alloys composition (50% at. Ni, 50% at.Ti) and (Ni 48% at., Ti 50% at., Sn 2% at.). The characteristics of both alloys were investigated by utilizing Differential Scanning Calorimetry, X- ray Diffraction Analysis, Scanning Electron Microscope, optical microscope and vicker's micro hardness test. The results showed that adding Sn element leads to decrease the phase transformation temperatures evidently. Both alloy samples contain NiTi matrix phase and Ti2Ni secondary phase, but the Ti2Ni phase content decreases with Sn addition and this is one of the reasons that leads to decrease the micro hardness of alloy with adding Sn element in a noticeable manner. The micro hardness decreases from 238.74 for NiTi equiatomic alloy to 202 for NiTiSn alloy after heat treatment.

Effect of Homogenization Time and Cooling Rate on Martensitic Transformations in Ti-57.5%wtNi Alloy

2010 ◽  
Vol 297-301 ◽  
pp. 339-343
Author(s):  
P. Movahed ◽  
Ali Shokuhfar ◽  
H. Kaffash ◽  
A. Etaati ◽  
H. Bolvardi ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Niti Alloy ◽  
Nickel Content ◽  
Martensitic Transformations ◽  
Graphite Crucible ◽  
Heat Treatments ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Scanning Calorimetry ◽  
Homogenization Time

NiTi alloys containing more than 55%wt nickel undergo precipitation of Ni4Ti3, Ni3Ti2, and Ni3Ti phases during various heat treatments which could have a great effect on the chemical composition of the matrix and behavior of alloy. In this investigation, a NiTi alloy with Ti-57.5%wt nickel content, produced by vacuum induction melting in a graphite crucible, were subjected to the homogenization heat treatments in 1100oC and for various time periods (0.5, 1, 2, and 4 hours). The subsequent cooling was conducted in different cooling media (furnace and air) in order to examine the effect of cooling rate. Microstructural investigations show Ni4Ti3 particles with bimodal size distribution in furnace cooling. Differential scanning calorimetry demonstrates the correlation between homogenization time and transformation temperatures of the alloy.

Influence of Heat Treatments on a NiTi Shape Memory Alloy Obtained Using Vacuum Induction Melting and Reprocessed by Plasma Skull Push-Pull

2015 ◽  
Vol 1765 ◽  
pp. 121-126 ◽  
Author(s):  
Jackson de Brito Simões ◽  
Francisco Fernando Roberto Pereira ◽  
Jorge Otubo ◽  
Carlos José de Araújo
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Electrical Resistance ◽  
Heat Treatments ◽  
Vacuum Induction Melting ◽  
Niti Shape Memory Alloy ◽  
Induction Melting ◽  
Thermal Treatments ◽  
Scanning Calorimetry ◽  
Thermally Induced

ABSTRACTShape memory alloys (SMA) are metallic attractive engineering materials due to their capacity to store pre-defined shapes through a thermally induced phase transition from a solid state. This paper aims to evaluate the influence of solubilization thermal treatments on a NiTi shape memory alloy originally fabricated by vacuum induction melting and then reprocessed by plasma melting followed by injection molding (Plasma Skull Push Pull process) into different metal molds (steel, aluminum, brass and copper) in order to compare the thermal properties regarding to its raw state. The thermal treatments of solubilization were carried out at 850°C in different times (2n function, n = 0, 1, 2 and 3, in hours). The influence of solubilizing treatments in the NiTi shape memory alloy was analyzed using the following characterization techniques: Differential Scanning Calorimetry (DSC) and Electrical Resistance as a function of Temperature (ERT). The results demonstrate that the solubilization heat treatments applied on the reprocessed NiTi shape memory alloy through the plasma skull push pull process, provides important changes in the phase transformation of the material. Therefore, it was demonstrated that it is necessary to solubilize the material after melting or remelting the NiTi shape memory alloy via this process to obtain mini-actuators products with homogeneous properties.

Effect of the linear velocity during the melt spinning process on shape memory transformation of Ni-Ti ribbons

2012 ◽  
Vol 1373 ◽  
Author(s):  
E. Nuñez-Mendoza ◽  
E. López Cuellar ◽  
Walman Benicio de Castro ◽  
B. López Walle
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Melt Spinning ◽  
Solidification Rate ◽  
Linear Velocity ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Scanning Calorimetry ◽  
Spinning Process ◽  
Niti Shape Memory Alloys

AbstractThe usual process to produce NiTi shape memory alloys is vacuum induction melting (VIM). Currently a new alternative process to produce NiTi shape memory alloys by rapid solidification structures called Melt Spinning has been studied. In this work, results of ribbons with a chemical composition Ti-55.2 Ni (wt %) alloy prepared by this method are presented. The ribbons are prepared at two different linear velocities: 30 m/s and 50 m/s. After that, samples are heat treated at 350 °C during 1 hour. The alloys are characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction. According to the cycled DSC test, transformation peaks are associated with the B2→R→B19´ transformation during cooling and B19´→R→B2 during heating, showing transformation in multi-peaks. The martensite B19´ start (Ms) is varying from 35 to 39°C and the martensite finish (Mf) from 15 to 21°C, 42-47°C for austenite B2 start (As) and 65-69°C for austenite finish (Af) approximately. All analyzed ribbons show very similar values of transformation hysteresis temperatures at 50% of transformation of around 28°C. In order to change solidification rate, linear velocity is varied during the melt spinning process. Results indicate that linear velocity affects directly the temperature of transformation. When the linear velocity is increasing, crystallographic Ti-rich precipitates are developed, but dendritic growth disappears, changing the microstructure and decreasing these transformation temperatures. Then changes in linear velocity can dramatically affect shape memory properties, and in this case a velocity of 50 m/s produces a more homogenous alloy.

Microstructure in soft magnetic E3 (S1, Al) (Sendust) alloys

1988 ◽  
Vol 46 ◽  
pp. 770-771
Author(s):  
June D. Kim
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Ternary Phase Diagram ◽  
Vertical Tube ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Soft Magnetic ◽  
Quenching Temperature ◽  
Thin Foils ◽  
Vertical Tube Furnace

Iron-base alloys containing 8-11 wt.% Si, 4-8 wt.% Al, known as “Sendust” alloys, show excellent soft magnetic properties. These magnetic properties are strongly dependent on heat treatment conditions, especially on the quenching temperature following annealing. But little has been known about the microstructure and the Fe-Si-Al ternary phase diagram has not been established. In the present investigation, transmission electron microscopy (TEM) has been used to study the microstructure in a Sendust alloy as a function of temperature.An Fe-9.34 wt.% Si-5.34 wt.% Al (approximately Fe3Si0.6Al0.4) alloy was prepared by vacuum induction melting, and homogenized at 1,200°C for 5 hrs. Specimens were heat-treated in a vertical tube furnace in air, and the temperature was controlled to an accuracy of ±2°C. Thin foils for TEM observation were prepared by jet polishing using a mixture of perchloric acid 15% and acetic acid 85% at 10V and ∼13°C. Electron microscopy was performed using a Philips EM 301 microscope.

UDIMET 700

Alloy Digest ◽  
1987 ◽  
Vol 36 (1) ◽  
Keyword(s):  
Gas Turbines ◽  
Base Alloy ◽  
Heat Treating ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Nickel Base Alloy ◽  
Vacuum Arc Remelting ◽  
Temperature Performance ◽  
Nickel Base

Abstract UDIMET 700 is a wrought nickel-base alloy produced by vacuum-induction melting and further refined by vacuum-arc remelting. It has excellent mechanical properties at high temperatures. Among its applications are blades for aircraft, marine and land-based gas turbines and rotor discs. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-51. Producer or source: Special Metals Corporation. Originally published March 1959, revised January 1987.

ALLVAC AC718

Alloy Digest ◽  
1991 ◽  
Vol 40 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Good Ductility

Abstract Allvac 718 is produced by vacuum induction melting followed by vacuum arc or electroslag consumable remelting. Th alloy has excellent strength and good ductility up to 1300 F (704 C). It also has excellent cryogenic properties. It has unique welding characteristics. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-394. Producer or source: Allvac Inc..

NICKELVAC N

Alloy Digest ◽  
1990 ◽  
Vol 39 (12) ◽  
Keyword(s):  
Solid Solution ◽  
Corrosion Resistance ◽  
Heat Treating ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Good Oxidation Resistance ◽  
Temperature Performance ◽  
Molten Fluoride ◽  
Fluoride Salts ◽  
Container Material

Abstract NICKEL VAC N was originally developed as a container material for molten fluoride salts. It is a moderate strength, solid solution strengthened alloy with good oxidation resistance to 1800 F. It has excellent resistance to fluoride salts in the range 1300-1600 F. It is produced by vacuum induction melting followed electroslag remelting. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-388. Producer or source: Teledyne Allvac.

NICKELVAC X-751

Alloy Digest ◽  
1990 ◽  
Vol 39 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Aluminum Content ◽  
Heat Treating ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Service Temperature ◽  
Maximum Service Temperature

Abstract NICKEL VAC X-751 is a modification of NICKEL VAC X-750 carrying higher aluminum content (0.90-1.50 vs 0.4-1.0%). This raises the maximum service temperature 100 F(55 C) to 1600 F(871 C). NICKEL VAC X-751 has a simplified and shortened heat treating cycle relative to NICKEL VAC X-750. It is produced by vacuum induction melting followed by vacuum arc or electroslag remelting. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-387. Producer or source: Teledyne Allvac.

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