Characterization on the Precipitates in the Ti-Ni-Al-Zr Alloy during Heat Treatment

2015 ◽  
Vol 727-728 ◽  
pp. 103-106 ◽  
Author(s):  
Li Yuan Sheng ◽  
Fang Yang ◽  
Ting Fei Xi
Keyword(s):  
Heat Treatment ◽  
Transformation Temperature ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Eutectic Microstructure ◽  
Eutectic Region ◽  
Sem And Tem ◽  
Heat Treated ◽  
Different Temperatures ◽  
Zr Alloy

In the present paper, the Ti-15Ni-6Al-2Zr alloy is fabricated and heat treated at different temperatures. Its microstructure and morphology of Ti2Ni phase are investigated by SEM and TEM. The results reveal that the Ti-15Ni-6Al-2Zr alloy is composed of eutectoid and eutectic microstructure, which possesses fine Ti2Ni fiber in eutectoid region and fine α-Ti phase in eutectic region. With the increase of heat treatment temperature, the amount of α-Ti and Ti2Ni phases decrease gradually. When the heat treatment temperature is higher than 900°C, almost no α-Ti phase is left. The transformation temperature of α-Ti phase to β-Ti phase is about 850°C, and the transformation of α-Ti phase promotes the decrease of Ti2Ni phase. During the heat treatment, the Ti2Ni fiber phase experiences the refining, fragmentation, coarsening and granulating.

Effect of Heat Treatment Temperature on the Mechanical Properties of Custom-Made NiTi Closed Coil Springs

2020 ◽  
Vol 897 ◽  
pp. 35-40
Author(s):  
Thanate Assawakawintip ◽  
Rochaya Chintavalakorn ◽  
Peerapong Santiwong ◽  
Anak Khantachawana
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Tensile Tests ◽  
Treatment Temperature ◽  
Statistical Analyses ◽  
Outer Diameter ◽  
Heat Treated ◽  
Custom Made ◽  
Different Temperatures

To investigate the effects of different temperatures for heat treatment of custom-made NiTi closed coil springs. NiTi closed coil springs (50.8% Ni-49.2%Ti) were manually fabricated around a 0.9mm diameter mandrel and heat treated at temperatures of 400°C, 450°C, and 500°C for 20 minutes. The outer diameter of each specimen was measured to determine the effect of heat treatment temperature on spring geometry. Tensile tests were carried out to measure the force levels at 3, 6, 9, and 12 mm of spring extension. Non-parametric statistical analyses were done to assess and compare the effects of different temperatures of heat treatment on the custom-made orthodontic closed coil springs. Heat treatment at lower temperatures produced larger outer coil diameters than at higher temperatures. Raising the temperature of heat treatment produced significant increases in force levels by 13-18 g especially between 400°C and 500°C at spring extensions of 3, 6 and 9 mm. The highest superelastic ratio of 5.44 was found in the NiTi coil springs that were heat treatment at 500°C for 20 minutes which signifies superelastic tendencies. The mechanical properties of NiTi closed coil springs are influenced by the temperature of heat treatment. The NiTi closed coil springs that were heat treated at 500°C for 20 minutes produce appropriate force levels to display a superelastic tendency for orthodontic use.

scholarly journals Shape Memory and Mechanical Properties of Cold Rolled and Annealed Fe-17Mn-5Si-5Cr-4Ni-1Ti-0.3C Alloy

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 255
Author(s):  
Dohyung Kim ◽  
Kinam Hong ◽  
Jeesoo Sim ◽  
Junghoon Lee ◽  
Wookjin Lee
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Shape Recovery ◽  
Treatment Temperature ◽  
Heat Treated ◽  
Different Temperatures ◽  
Annealing Heat Treatment ◽  
Cold Rolled ◽  
Annealing Heat

In the present study, the shape, memory, and mechanical properties of cold-rolled and annealed Fe-17Mn-5Si-5Cr-4Ni-1Ti-0.3C (wt.%) alloy were investigated. The cold-rolled alloy was annealing heat-treated at different temperatures in the range of 500–900 °C for 30 min. The shape recovery behavior of the alloy was investigated using strip bending test followed by recovery heating. The microstructural evolution and the stress-strain response of the alloy heat-treated at different temperatures revealed that the recovery took place at a heat-treatment temperature higher than 600 °C. Recrystallization occurred when the heat-treatment temperature was higher than 800 °C. Meaningful shape recovery was observed only when the alloy was annealed at temperatures higher than 600 °C. The highest recovery strain of up to 2.56% was achieved with a pre-strain of 5.26% and recovery heating temperature of 400 °C, when the alloy was heat-treated at 700 °C. Conversely, the yield strength reduced significantly with increasing annealing heat-treatment temperature. The experimental observations presented in this paper provide a guideline for post-annealing heat-treatment when a good compromise between mechanical property and shape recovery performance is required.

scholarly journals Water Resistance and Creep Behavior of Heat-Treated Moso Bamboo Determined by the Stepped Isostress Method

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1264
Author(s):  
Teng-Chun Yang ◽  
Tung-Lin Wu ◽  
Chin-Hao Yeh
Keyword(s):  
Heat Treatment ◽  
Water Absorption ◽  
Creep Behavior ◽  
Heat Treatment Temperature ◽  
Water Resistance ◽  
Absorption Efficiency ◽  
Treatment Temperature ◽  
Moso Bamboo ◽  
Phyllostachys Pubescens ◽  
Heat Treated

The influence of heat treatment on the physico-mechanical properties, water resistance, and creep behavior of moso bamboo (Phyllostachys pubescens) was determined in this study. The results revealed that the density, moisture content, and flexural properties showed negative relationships with the heat treatment temperature, while an improvement in the dimensional stability (anti-swelling efficiency and anti-water absorption efficiency) of heat-treated samples was observed during water absorption tests. Additionally, the creep master curves of the untreated and heat-treated samples were successfully constructed using the stepped isostress method (SSM) at a series of elevated stresses. Furthermore, the SSM-predicted creep compliance curves fit well with the 90-day full-scale experimental data. When the heat treatment temperature increased to 180 °C, the degradation ratio of the creep resistance (rd) significantly increased over all periods. However, the rd of the tested bamboo decreased as the heat treatment temperature increased up to 220 °C.

Effect of Heat Treatment on the Microstructure and Property of TiAl Alloys Prepared by Gas Atomization Powders

2013 ◽  
Vol 747-748 ◽  
pp. 497-501
Author(s):  
Na Liu ◽  
Zhou Li ◽  
Guo Qing Zhang ◽  
Hua Yuan ◽  
Wen Yong Xu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Tial Alloy ◽  
Lamellar Microstructure ◽  
Treatment Temperature ◽  
Gas Atomization ◽  
Thermally Induced ◽  
Heat Treated ◽  
Fine Duplex ◽  
Step Heat Treatment

Powder metallurgical TiAl alloy was fabricated by gas atomization powders, and the effect of heat treatment temperature on the microstructure evolution and room tensile properties of PM TiAl alloy was investigated. The uniform fine duplex microstructure was formed in PM TiAl based alloy after being heat treated at 1250/2h followed by furnace cooling (FC)+ 900/6h (FC). When the first step heat treatment temperature was improved to 1360/1h, the near lamellar microstructure was achieved. The ductility of the alloy after heat treatment improved markedly to 1.2% and 0.6%, but the tensile strength decreased to 570MPa and 600MPa compared to 655MPa of as-HIP TiAl alloy. Post heat treatment at the higher temperature in the alpha plus gamma field would regenerate thermally induced porosity (TIP).

Mechanical and Superelastic Properties of Au-51Ti-18Co Biomedical Shape Memory Alloy Heat-Treated at 1173 K to 1373 K

2016 ◽  
Vol 97 ◽  
pp. 141-146 ◽  
Author(s):  
Taywin Buasri ◽  
Hyunbo Shim ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Kenji Goto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Critical Stress ◽  
Biomedical Applications ◽  
Shape Recovery ◽  
Treatment Temperature ◽  
Recovery Ratio ◽  
Recovery Strain ◽  
Heat Treated ◽  
Alloy Heat

The effect of heat treatment temperature from 1173 K to 1373 K for 3.6 ks on mechanical and superelastic properties of an Ni-free Au-51Ti-18Co alloy (mol%) was investigated. The stress for inducing martensitic transformation (SIMT) and the critical stress for slip deformation (CSS) slightly decrease with increasing the heat–treatment temperature. Regardless of heat–treatment temperature, good superelasticity was definitely recognized with the maximum shape recovery ratio up to 95 % and 4 % superelastic shape recovery strain. As the mentioned reasons, the Au-51Ti-18Co alloy is promising for practical biomedical applications.

Investigation of Heat Treated Electrodeposited CoNiFe on Microstructure and Hardness

2015 ◽  
Vol 1113 ◽  
pp. 56-61
Author(s):  
Nor Azrina Resali ◽  
Koay Mei Hyie ◽  
M.N. Berhan ◽  
C.M. Mardziah
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Crystallographic Structure ◽  
Face Centered Cubic ◽  
Heat Treated ◽  
Hardness Property ◽  
Finishing Process ◽  
The Face ◽  
Face Centered

In this research, heat treatment is the final finishing process applied on nanocrystalline CoNiFe to improve microstructure for good hardness property. Nanocrystalline CoNiFe has been synthesized using the electrodeposition method. This study investigated the effect of heat treatment at 500°C, 600°C, 700°C and 800°C on electrodeposited nanocrystalline CoNiFe. The heat treatment process was performed in the tube furnace with flowing Argon gas. By changing the heat treatment temperature, physical properties such as phase and crystallographic structure, surface morphology, grain size and hardness of nanocrystalline CoNiFe was studied. The nanocrystalline CoNiFe phase revealed the Face Centered Cubic (FCC) and Body Centered Cubic (BCC) crystal structure. FESEM micrographs showed that the grain sizes of the coatings were in the range of 78.76 nm to 132 nm. Dendrite shape was found in the microstructure of nanocrystalline CoNiFe. The nanocrystalline CoNiFe prepared in heat treatment temperature of 700°C, achieved the highest hardness of 449 HVN. The surface roughness of nanocrystalline CoNiFe heated at 700°C was found to be smaller than other temperatures.

Effects of Heat-Treatment Temperature on the Properties of Negative CTE Eucryptite Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 123-125 ◽  
Author(s):  
Yong Li ◽  
Qi Hong Wei ◽  
Ling Li ◽  
Chong Hai Wang ◽  
Xiao Li Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Heat Treatment Temperature ◽  
Bending Strength ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Treatment Temperature ◽  
Heat Treated

In this paper, negative thermal expansion coefficient eucryptite powders were prepared by sol-gel method using silica-sol as starting material. The raw blocks were obtained by dry pressing process after the powder was synthesized, and then the raw blocks were heat-treated at 600º, 1150º, 1280º, 1380º, 1420º and 1450°C, respectively. Variations of density, porosity and thermal expansion coefficient at different heat treatment temperatures were investigated. Phase transformation and fracture surface morphology of eucryptite heat-treated at different temperatures, respectively, were observed by XRD and SEM. The results indicate that, with the increasing heat- treatment temperature, the grain size and the bending strength increased, porosity decreased, thermal expansion coefficient decreased continuously. Negative thermal expansion coefficient of -5.3162×10-6~-7.4413×10-6 (0~800°C) was obtained. But when the heat-treatment temperature was more than 1420°C, porosity began to increase, bending strength began to decrease, which were the symbols of over-burning, while the main crystal phase didn’t change.

scholarly journals Effect of Heat Treatment Temperature on Martensitic Transformation and Superelasticity of the Ti49Ni51 Shape Memory Alloy

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2539 ◽  
Author(s):  
Peiyou Li ◽  
Yongshan Wang ◽  
Fanying Meng ◽  
Le Cao ◽  
Zhirong He
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Thermal Hysteresis ◽  
Treatment Temperature ◽  
Heat Treated ◽  
Different Temperatures ◽  
Tini Phase ◽  
Rapidly Solidified

The martensitic transformation and superelasticity of Ti49Ni51 shape memory alloy heat-treatment at different temperatures were investigated. The experimental results show that the microstructures of as-cast and heat-treated (723 K) Ni-rich Ti49Ni51 samples prepared by rapidly-solidified technology are composed of B2 TiNi phase, and Ti3Ni4 and Ti2Ni phases; the microstructures of heat-treated Ti49Ni51 samples at 773 and 823 K are composed of B2 TiNi phase, and of B2 TiNi and Ti2Ni phases, respectively. The martensitic transformation of as-cast Ti49Ni51 alloy is three-stage, A→R→M1 and R→M2 transformation during cooling, and two-stage, M→R→A transformation during heating. The transformations of the heat-treated Ti49Ni51 samples at 723 and 823 K are the A↔R↔M/A↔M transformation during cooling/heating, respectively. For the heat-treated alloy at 773 K, the transformations are the A→R/M→R→A during cooling/heating, respectively. For the heat-treated alloy at 773 K, only a small thermal hysteresis is suitable for sensor devices. The stable σmax values of 723 and 773 K heat-treated samples with a large Wd value exhibit high safety in application. The 773 and 823 K heat-treated samples have large stable strain–energy densities, and are a good superelastic alloy. The experimental data obtained provide a valuable reference for the industrial application of rapidly-solidified casting and heat-treated Ti49Ni51 alloy.

Effect of Heat Treatment on the Combustion Characteristics of a Lignite

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Zhezi Zhang ◽  
Mingming Zhu ◽  
Jianbo Li ◽  
Kai Zhang ◽  
Guoqing Shen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Ignition Delay ◽  
Delay Time ◽  
Heat Treatment Temperature ◽  
Ignition Delay Time ◽  
Treatment Temperature ◽  
Ftir Analysis ◽  
Single Particles ◽  
Heat Treated ◽  
Ignition And Combustion

In this study, the ignition and combustion behavior of raw and heat-treated single particles of lignite were experimentally investigated, with a focus on the effect of heat treatment temperatures. The lignite particles were heat treated to various final temperatures (473, 623 and 773 K) in nitrogen and characterized using proximate, ultimate, and Fourier transform infrared spectroscopy (FTIR) analysis. A single lignite particle of 2 or 3 mm in diameter was suspended on a silicon carbide fiber and burned in air in a horizontal tube furnace operating at 1123 K. The ignition and combustion process of the particle was record using a color CCD camera at 25 fps. The ignition mechanism, ignition delay time, volatile flame duration, and burnout time of the single particles were examined by processing the recorded images. The proximate and ultimate analysis results indicated that the volatile matter and oxygen contents decreased, while the carbon content increased with increasing temperature of heat treatment. This trend was consistent with observations in the FTIR analysis, in which the intensity of oxygen-containing functional groups decreased with increasing the heat treatment temperature. The ignition of raw and heat treated lignite particles followed a joint hetero-homogeneous mechanism under all conditions studied. The ignition delay time, volatile flame extinction time, and the total combustion time decreased with increasing heat treatment temperature up to 623 K. A further increase in the heat treatment temperature to 773 K resulted in prolonged key ignition and combustion characteristic times.

Effect of Heat Treatment on the Reactivity and Crystallinity of Coal-Char

2005 ◽  
Author(s):  
Shouyu Zhang ◽  
Junfu Lu ◽  
Jianmin Zhang ◽  
Qing Liu ◽  
Guangxi Yue
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Treatment Time ◽  
Treatment Temperature ◽  
Coal Char ◽  
Heat Treatment Time ◽  
Heat Treat ◽  
Heat Treated ◽  
Layer Stacking ◽  
Crystalline Growth

The effect of heat treatment on the reactivity and crystallinity of char prepared from the vitrinite of two coals (YX, JJ) was investigated by using XRD and TGA in this paper. The results from TGA show that the reactivity of the chars from YXV and JJV decreases with the increase of heat treatment temperature. The reactivity of YXV char decreases quickly and significantly as heat treatment time increases. However, after heat treatment time of 60 min, it decreases slowly. The effect of heat treatment time on the reactivity of JJV char is small. The results from XRD show that the crystallinity of coal-char is determined by the intensity of heat treatment. When heat treatment time is more than 60 minutes, the turbostratic crystallite of YXV char prepared under 900°C changes remarkably and becomes more orderly. The aromatic layer stacking heights (Lc) of YXV Char when heat treated above 900°C increased with the increase of heat treatment time. The effect of heat treat time on Lc of JJV char is small, but under heat treatment temperature of 1200°C, the crystalline of JJV char grows distinctly. There is a good parallel relationship between the crystalline growth and deactivation of the chars. It can be concluded that the growth of the crystalline is the main reason for the deactivation of coal-char.

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