Effect of Direct Electric Resistance Heat Treatment on Mechanical Properties of NiTi Orthodontic Arch Wires

2008 ◽  
Vol 55-57 ◽  
pp. 249-252 ◽  
Author(s):  
W. Kiattiwongse ◽  
Anak Khantachawana ◽  
P. Santiwong
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Bending Test ◽  
Electric Resistance ◽  
Bending Tests ◽  
Three Point Bending ◽  
Heat Treated ◽  
Different Types ◽  
Orthodontic Archwires ◽  
A Current

Two types of rectangular orthodontic archwires; NiTiTM and 40oCuNiTi, were heat treated by Direct Electric Resistance Heat Treatment (DERHT) using different electric currents for 4 s. Their mechanical properties were then evaluated by micro hardness and three-point bending tests. After applying 4.5-5.5 A current, the hardness of NiTiTM increased with the increased current, whereas the change in hardness of 40oCuNiTi was slight. When 6 A current was applied, the hardness of the midspan of both wires significantly decreased. From the three-point bending test, unloading forces of NiTiTM increased after treating with 5.5 A current, while those of 40oCuNiTi decreased. However, both specimens lost their superelasticity when applied with 6 A current. In conclusion, after DERHT, various changes in mechanical properties can be noted in the different types of nickel titanium archwire.

Formability of Ultrafine-Grained AA6016 Sheets Processed by Accumulative Roll Bonding

2012 ◽  
Vol 504-506 ◽  
pp. 575-580 ◽  
Author(s):  
Tina Hausöl ◽  
Christian W. Schmidt ◽  
Verena Maier ◽  
Wolfgang Böhm ◽  
Hung Nguyen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Laser Heat Treatment ◽  
Bending Tests ◽  
Roll Bonding ◽  
Laser Heat ◽  
Heat Treated ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure ◽  
Bending Behaviour

Aluminium alloy AA6016 was accumulative roll bonded up to eight cycles in order to produce an ultrafine-grained microstructure. The formability of these sheets was investigated by means of bending tests. Furthermore the influence of a local laser heat treatment at the bending edge is observed. The strength of the UFG samples is increased by a factor of around two compared to the conventionally grained T4 condition which also results in up to 50 % higher punch forces needed for bending of ARB processed samples. An anisotropic bending behaviour is observed. By applying a tailored laser heat treatment along the bending edge prior to the bending tests a local recrystallization and recovery at the deformation zone of the samples is achieved. Thus, ductility is increased locally whereby bending to an angle of 80° is possible with lower forming forces compared to the non-heat treated specimens. The results are compared to previous studies on mechanical properties and formability investigations of ARB processed AA6016.

scholarly journals Influence of the Infill Orientation on the Properties of Zirconia Parts Produced by Fused Filament Fabrication

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3158 ◽  
Author(s):  
Santiago Cano ◽  
Tanja Lube ◽  
Philipp Huber ◽  
Alberto Gallego ◽  
Juan Alfonso Naranjo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Complex Geometries ◽  
Fused Filament Fabrication ◽  
Moisture Evaporation ◽  
Bending Tests ◽  
Three Point Bending ◽  
Different Types ◽  
Fill Pattern ◽  
The Many

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.

Assessment of Mechanical Properties and Transformation Behavior of Locally-Made Ni-Ti Alloys Used in Orthodontics

2008 ◽  
Vol 55-57 ◽  
pp. 245-248 ◽  
Author(s):  
Nattiree Chiranavanit ◽  
Anak Khantachawana ◽  
N. Anuwongnukroh ◽  
Surachai Dechkunakorn
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Testing Machine ◽  
Optical Microscope ◽  
Treatment Temperature ◽  
Bending Test ◽  
Hardness Tester ◽  
Ti Alloys ◽  
Heat Treated ◽  
Average Grain Size

Ni-Ti alloy wires have been widely used in clinical orthodontics because of their properties of superelasticity (SE) and shape memory effect (SME). The purpose of this study was to assess the mechanical properties and phase transformation of 50.7Ni-49.3 Ti (at%) alloy (NT) and 45.2Ni-49.8Ti-5.0Cu (at%) alloy (NTC), cold-rolled with various percent reductions. To investigate SE and SME, heat-treatment was performed at 400°C and 600°C for 1 h. The specimens were examined using an Energy-Dispersive X-ray Spectroscope (EDS), Differential Scanning Calorimeter (DSC), Universal Testing Machine (Instron), Vickers Hardness Tester and Optical Microscope (OM). On the three-point bending test, the superelastic load-deflection curve was seen in NTC heat-treated at 400°C. Furthermore, NT heat-treated at 400°C with 30% reduction produced a partial superelastic curve. For SME, no conditions revealed superelasticity at the oral temperature. Micro-hardness value increased with greater percentage reduction. The average grain size for all specimens was typically 55-80 µm. The results showed that locally-made Ni-Ti alloys have various transformation behaviors and mechanical properties depending on three principal factors: chemical composition, work-hardening (the percent reduction) and heat-treatment temperature.

Effect of High-Temperature Heat Treatment on Mechanical Property of Cr-Geopolymer Composite

2011 ◽  
Vol 399-401 ◽  
pp. 469-473
Author(s):  
Mei Rong Wang ◽  
Yi Zheng ◽  
De Chang Jia ◽  
Yu Zhou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Property ◽  
Treatment Temperature ◽  
Bending Test ◽  
Chromium Powder ◽  
Three Point Bending ◽  
High Temperature Heat Treatment ◽  
Micro Cracks ◽  
Before And After

Chromium powder reinforced geopolymer composite (Cr/geopolymer) was prepared in order to enhance its thermal conductivity and mechanical properties. The phase composition, microstructure and mechanical properties of Cr/geopolymer before and after heat treatment at 900, 1000, 1100 and 1200°C were investigated by the X–ray diffraction (XRD), scanning electron microscopy (SEM) and three–point bending test. With increasing heat treatment temperature from 900 to 1100°C, mechanical property of Cr/geopolymer increased gradually and at 1100°C flexural strength got the peak value, which was 325% higher than that of specimens without heat treatment. Cr/geopolymer treated at 900°C did not completely transform into crystalline phase, and many micro cracks around the chromium particles were observed. Cr/geopolymer treated at 1000–1100°C completely crystallized into leucite phase, and the metal chromium remained its original state. Meanwhile, most of the micro cracks were closed. When the temperature further increased to 1200°C, many visible defects were observed in Cr/geopolymer, and chromium oxide appeared in the interface of Cr/geopolymer, which had detrimental effect on the heat conduction and mechanical property of the composite.

A study on mechanical properties of Al5052/CFRP/Al5052 composite through three-point bending tests and shear lap tests according to surface roughness

2016 ◽  
Vol 54 (12) ◽  
pp. 1549-1559 ◽  
Author(s):  
MS Lee ◽  
SJ Kim ◽  
OD Lim ◽  
CG Kang
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Bending Test ◽  
Shear Load ◽  
Side View ◽  
Bending Tests ◽  
Three Point Bending ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Hybrid Sample

In this study, aluminum samples with various microsurface roughness values were produced by sandblasting to investigate the effect of the Ra (Surface roughness) value on the samples’ mechanical properties. Toward this end, a carbon fiber reinforced plastic/Al5052 hybrid sample was produced, and its mechanical properties were investigated through a tensile test, three-point bending test, and shear lap test. The theoretical and experimental tensile strength values of the hybrid composite were compared. During the bending test, CFRP and AI5052 separated in untreated specimens. A side-view examination revealed that the adhesion was best when the surface roughness was greatest ( Ra = 1.2 µm). Furthermore, shear load increased with the surface roughness. Therefore, the surface treatment was a crucial factor in making the specimen surface even and in increasing the roughness and therefore improving adhesion.

scholarly journals EVALUATION OF THE MECHANICAL PROPERTIES AND SURFACE TOPOGRAPHY OF AS-RECEIVED, IMMERSED AND AS-RETRIEVED ORTHODONTIC ARCHWIRES

2017 ◽  
Vol 90 (3) ◽  
pp. 313-326
Author(s):  
Silvia Izabella Pop ◽  
Mircea Dudescu ◽  
Violeta Valentina Merie ◽  
Mariana Pacurar ◽  
Cristina Dana Bratu
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Stainless Steel ◽  
Tensile Testing ◽  
Nickel Titanium ◽  
Bending Tests ◽  
Three Point Bending ◽  
Beta Titanium ◽  
Carbonated Drinks ◽  
Orthodontic Archwires

Background and aims. This experimental study mainly aims at comparing the most important mechanical properties of the new orthodontic archwires, those immersed in fluorinated solution, the as-retrieved ones and  the intra-oral used ones.Methods. A total of 270 arch wires were tested, using tensile testing and three-point bending tests. The tested archwires were made of Stainless Steel, Nickel Titanium, Beta-Titanium and physiognomic covered Nickel Titanium. The tested archwires were subjected to three types of treatments: immersion into fluorinated solution, immersion into carbonated drinks and intra-oral use.Results. The immersion caused variations of the activation and deactivation forces of all arch wires. The most affected arch wires, in terms of bending characteristics,  were the intra-oral used ones.Conclusions. The alteration of mechanical properties of the orthodontic arch wires by their immersion into fluorinated solutions and soft drinks could not be statistically demonstrated.

Evaluation of Mechanical Properties of Polyester Composite with Graphene and Graphite through Three-Point Bending Test

2014 ◽  
Vol 659 ◽  
pp. 22-27 ◽  
Author(s):  
Marian Bastiurea ◽  
Magdalena Silvia Rodeanu ◽  
Dumitru Dima ◽  
Monica Murarescu ◽  
Gabriel Andrei
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Electrical Properties ◽  
Polymer Composites ◽  
Bending Test ◽  
Bending Tests ◽  
Three Point Bending ◽  
Polyester Composite ◽  
Thermal And Electrical Properties ◽  
Polyester Composites

Graphenes have aroused great interest among the scientists lately, due to their special physical properties which are supposed to be transferred to composite materials [1,2,3,6]. Some polymers show low mechanical properties which can be improved by adding various types of materials [9,13]. Using nanoparticles, an enhancement of mechanical, thermal and electrical properties can be obtained, even for small contents of additives [10,11,12,14,15,16]. The evaluation of mechanical properties of polymer composites with graphene can be achieved relying on the three-point bending tests [4]. This work presents a few conclusions resulting from the three points bending tests of the polyester composites with graphene and graphite [7,8].

Mechanical Properties of Several NiTi Alloy Wires in Three-Point Bending Tests

2011 ◽  
Vol 87 ◽  
pp. 14-19 ◽  
Author(s):  
Surachai Dechkunakorn ◽  
Rutchadakorn Isarapatanapong ◽  
Niwat Anuwongnukroh ◽  
Nattiree Chiranavanit ◽  
Julathep Kajorchaiyakul ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Niti Alloy ◽  
Bending Test ◽  
Dental Arch ◽  
Orthodontic Wires ◽  
Niti Wire ◽  
Bending Tests ◽  
Three Point Bending ◽  
Loading And Unloading ◽  
Deflection Rate

Objective: To clarify mechanical properties of 14 superelastic NiTi orthodontic wires by three-point bending tests. Materials and Methods: The three-point bending test was conducted with a midspan deflection rate of 5 mm/min under constant temperature range 36±1°C. Wires were deflected to 3.1 mm. All data were recorded during the unloading process at deflections 3, 2, 1 and 0.5 mm. to simulate the force a wire exerts as a tooth is moved into the dental arch from a position of malocclusion. Results: The delivered forces changed slightly when the deflection varied during loading and unloading. Sentalloy wire applied the lowest continuous force. Conclusions: Commercial wires may not behave similarly due to minor differences in the production process, and force varies greatly from brand to brand. NiTi wire brands must be selected carefully considering the severity of malocclusion and stage of orthodontic treatment.

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

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