Accuracy of third-order bends of nickel-titanium wires and the effect of high and low pressure during memorizing heat treatment

2004 ◽  
Vol 126 (4) ◽  
pp. 476-484 ◽  
Author(s):  
Thomas Stamm ◽  
Ariane Hohoff ◽  
Dirk Wiechmann ◽  
Jan Sütfeld ◽  
Dirk Helm
Keyword(s):  
Heat Treatment ◽  
Low Pressure ◽  
Nickel Titanium ◽  
Third Order

Application of MeV Ion Implantation in the Formation of Nano-Metallic Clusters in Silica

1996 ◽  
Vol 457 ◽  
Author(s):  
D. Ila ◽  
Z. Wu ◽  
R. L. Zimmerman ◽  
S. Sarkisov ◽  
C. C. Smith ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Optical Absorption ◽  
Rutherford Backscattering Spectrometry ◽  
Treatment Temperature ◽  
Gold Clusters ◽  
Third Order ◽  
The Third ◽  
Pure Silica ◽  
Photorefractive Materials ◽  
Electric Susceptibility

ABSTRACTThe implantation of metal ions into photorefractive materials followed by thermal annealing leads to an increase in resonance optical absorption as well as an enhancement of the nonlinear optical properties. We have implanted ions of Au (3.6 MeV), Ag (1.5 MeV) and Cu (2.0 MeV) into pure silica followed by careful heat treatment. Using optical absorption spectrophotometry and rutherford backscattering spectrometry we have measured the cluster size for each heat treatment temperature and determined the activation energies for their formation. The third order electric susceptibility for silica with 2 nm gold clusters has been determined by Z-scan to be 65×10−8 esu.

scholarly journals Influence of Different Heat Treatments on Torsional and Cyclic Fatigue Resistance of Nickel–Titanium Rotary Files: A Comparative Study

2020 ◽  
Vol 10 (16) ◽  
pp. 5604 ◽  
Author(s):  
Gianluca Gambarini ◽  
Andrea Cicconetti ◽  
Dario Di Nardo ◽  
Gabriele Miccoli ◽  
Alessio Zanza ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Sem Analysis ◽  
Nickel Titanium ◽  
Torsional Resistance ◽  
Heat Treated ◽  
Torsional Test ◽  
Time To Fracture ◽  
Flexural Resistance

Protaper Universal (PTU), Protaper Gold (PTG) (Maillefer, Ballaigues, CH), EdgeTaper (ET), and EdgeTaper Platinum (ETP) (Albuquerque, NM, USA) were tested for both torsional and flexural resistance. The aim of the present study was to evaluate the influence of proprietary heat treatment on the metallurgical properties of the aforementioned instruments. Four groups of 30 different instruments (size 20.07) were tested, then divided into two subgroups of 15 instruments—one for the cyclic fatigue test in a curved canal (90°—2 mm radius) at 300 rpm and 2.5 Ncm. The time to fracture (TtF) and fragment length (FL) were recorded. The other subgroup was subjected to the torsional test (300 rpm, 5.5 Ncm). The torque to fracture and TtF were recorded. All the instruments underwent a SEM analysis. The heat-treated instruments showed a significantly higher fatigue resistance than the non-heat-treated instruments (p < 0.05). No significant differences were found in the torsional resistance between the ET and PTU, and the ETP and PTG. However, when comparing all the groups, the heat-treated instruments showed less torsional resistance. The improvement from heat treatment was mainly found in the cyclic fatigue resistance.

Influence of Heat Treatment of Nickel-Titanium Rotary Endodontic Instruments on Apical Preparation: A Micro–Computed Tomographic Study

2015 ◽  
Vol 41 (12) ◽  
pp. 2031-2035 ◽  
Author(s):  
Bernardo Corrêa de Almeida ◽  
Fabíola Ormiga ◽  
Marcos César Pimenta de Araújo ◽  
Ricardo Tadeu Lopes ◽  
Inayá Corrêa Barbosa Lima ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Nickel Titanium ◽  
Computed Tomographic

Low pressure r.f. nitriding of austenitic stainless steel in an industrial-style heat-treatment furnace

1999 ◽  
Vol 345 (1) ◽  
pp. 113-118 ◽  
Author(s):  
J.M. Priest ◽  
M.J. Baldwin ◽  
M.P. Fewell ◽  
S.C. Haydon ◽  
G.A. Collins ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Pressure ◽  
Heat Treatment Furnace ◽  
Treatment Furnace

Study on After-Forging Austenite Recrystallization Rule of Low-Pressure Rotor Steel 26Cr2Ni4MoV with Thermo-Torsion Method

2009 ◽  
Vol 628-629 ◽  
pp. 635-640
Author(s):  
Li Yong Ni ◽  
Peng Chao Kang ◽  
Zhu Bai Liu ◽  
Wen Hua Yang
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Static Recrystallization ◽  
Low Pressure ◽  
Nucleation And Growth ◽  
Rotor Steel ◽  
Theoretical Base ◽  
Torsion Experiment ◽  
Austenite Recrystallization

In order to investigate the nucleation and growth of after-forging static recrystallization of low-pressure rotor steel 26Cr2Ni4MoV, the thermo-torsion experiment was conducted at 900°C,1000°C and 1100°C, respectively. The outer deformation of the used specimens was 0.21. The specimens were kept under a certain temperature for different periods. Results show that the recrystallization grain grew slowly at 900°C and the grain size became even after 30 minutes. The sizes of most grains were almost constant and only several grains grew bigger after 60 minutes. When the specimens were kept at 1000°C and 1100°C for one minute, static recrystallization was completed and the grain size was even. The said research could provide theoretical base for the controlled forging and after-forging heat treatment.

scholarly journals Advances in Low Pressure Carburizing and High-Pressure Gas Quenching

2021 ◽  
Author(s):  
Volker Heuer
Keyword(s):  
Heat Treatment ◽  
High Pressure ◽  
Single Layer ◽  
Low Pressure ◽  
Case Hardening ◽  
Significant Progress ◽  
Practical Applications ◽  
Cycle Times ◽  
Manufacturing Line ◽  
Gas Quenching

Abstract Low Pressure Carburizing (LPC) in combination with High Pressure Gas Quenching (HPGQ) has been established as an advanced and robust technology for case hardening. The process can be applied with batches consisting of multiple layers as well as batches consisting of single-layers. The paper shows the latest progress in LPC and HPGQ for the heat treatment of automotive and aerospace components. Significant progress has been made by continuous improvements in the fields of- Fixturing / load densities,- Reduction of cycle times,- Control of distortion,- Digitalization / Automation,- Quality control and- Integration of heat treatment into the manufacturing line. Practical applications are shown for both multiple- and single layer treatment.

Phase Transformations in Sputtered Ni-Ti Film: Effects of Heat Treatment and Precipitates

1991 ◽  
Vol 230 ◽  
Author(s):  
J. D. Busch ◽  
Mitchell H. Berkson ◽  
A. D. Johnson
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Nickel Titanium ◽  
Transformation Temperatures ◽  
Free Film ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Isothermal Heat Treatments

AbstractThis research investigated the influence of heat treatment and precipitation on the phase transformation temperatures of sputter-deposited nickel-titanium films. Films 5 to 10 microns thick were subjected to isochronal and isothermal heat treatments in vacuum. Four-point resistance measutements were made and the TP, TR, Ma, and Mc temperatures identified. The correlation between transformation temperatures and the film's microstructure was studied using transmission electron microscopy. Existence of Ti2Ni and Ti11Ni14 precipitates was seen to adversely influence the phase transformation temperatures. It was concluded that precipitate-free film is preferable for mechanical actuator applications.

scholarly journals The influence of distal-end heat treatment on deflection of nickel-titanium archwire

2016 ◽  
Vol 21 (1) ◽  
pp. 83-88
Author(s):  
Marcelo Faria da Silva ◽  
Célia Regina Maia Pinzan-Vercelino ◽  
Júlio de Araújo Gurgel
Keyword(s):  
Heat Treatment ◽  
Statistical Significance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Distal Portion ◽  
Nickel Titanium ◽  
Control Group ◽  
Orthodontic Wires ◽  
Niti Wires

Objective: The aim of this in vitro study was to evaluate the deflection-force behavior of nickel-titanium (NiTi) orthodontic wires adjacent to the portion submitted to heat treatment. Material and Methods: A total of 106 segments of NiTi wires (0.019 x 0.025-in) and heat-activated NiTi wires (0.016 x 0.022-in) from four commercial brands were tested. The segments were obtained from 80 archwires. For the experimental group, the distal portion of each segmented archwire was subjected to heat treatment (n = 40), while the other distal portion of the same archwire was used as a heating-free control group (n = 40). Deflection tests were performed in a temperature-controlled universal testing machine. Unpaired Student's t-tests were applied to determine if there were differences between the experimental and control groups for each commercial brand and size of wire. Statistical significance was set at p < 0.05. Results: There were no statistically significant differences between the tested groups with the same size and brand of wire. Conclusions: Heat treatment applied to the distal ends of rectangular NiTi archwires does not permanently change the elastic properties of the adjacent portions.

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