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.

The Effect of Heat Treatment on Fatigue and Mechanical Properties of 6061 Aluminium Alloy

2014 ◽  
Vol 699 ◽  
pp. 227-232
Author(s):  
Nurulhilmi Zaiedah Nasir ◽  
Mohd Ahadlin Mohd Daud ◽  
Mohd Zulkefli Selamat ◽  
Ahmad Rivai ◽  
Sivakumar Dhar Malingam
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Strength ◽  
Aluminium Alloy ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
Hardness Tester ◽  
Quenching Media ◽  
Heat Treated ◽  
6061 Aluminium Alloy

This paper investigated the effect of heat treatment on mechanical properties and microstructure of 6061 aluminium alloy. The aluminium alloys were examined in the heat treated conditions, using different quenching media, water and oil. The alloy was solution heat treated at temperature of 529oC for one, three and five hour respectively. Aging treatment was carried out at temperature of 160oC which is assumed to be the best temperature for ageing process. Hardness measurement was carried out using a Brinell Hardness Tester Machine. The results shows hardness and impact strength are inversely proportional to each other, as the hardness of 6061 aluminium alloy decreases and impact strength increases.

Effect of Sc on As-Cast Microstructures and Mechanical Properties of Al-Si-Mg-Cu-Ti Alloys

2017 ◽  
Vol 732 ◽  
pp. 32-37 ◽  
Author(s):  
Ming He Wang ◽  
Xiao Dong Du ◽  
Yu Kun Li ◽  
Zhen Zhang ◽  
Hai Lin Su ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Testing Machine ◽  
Ti Alloys ◽  
Universal Testing ◽  
Transmission Electron ◽  
Heat Treated ◽  
Eutectic Si ◽  
Microstructures And Mechanical Properties ◽  
Equiaxed Grain

The as-cast microstructures and mechanical properties of Al-Si-Mg-Cu-Ti alloys with and without Sc were investigated by metallographic microscope, field emission scanning electron microscope, energy spectrum analysis, transmission electron microscope and universal testing machine. The result shows that adding 0.20wt.% Sc into the casting alloy can refine the grain, change the growth morphology from dendrite to fine equiaxed grain, and the morphology of eutectic Si by rough laminar structure into fine fibrous. The tensile strength of alloy with 0.20wt.% Sc is up to 304.4 MPa after T6 heat treated, which is close to that of 6061 forging aluminum alloy.

Analysis on the Reasons of 500kV High-Voltage Disconnectors Hoop Fracture

2014 ◽  
Vol 915-916 ◽  
pp. 992-995
Author(s):  
Shuang Liu ◽  
Wei Tan Cui ◽  
Hong Wu Zhang ◽  
Yong Quan Ma
Keyword(s):  
Mechanical Properties ◽  
High Voltage ◽  
Chemical Elements ◽  
Testing Machine ◽  
Optical Microscope ◽  
Test Results ◽  
Tightening Force ◽  
Hardness Tester ◽  
Universal Testing ◽  
Fracture Appearance

The fracture reasons of 500kV high-voltage disconnectors hoops were analyzed. The fracture appearance, composition of chemical elements, metallographic, mechanical properties of the fractured hoops were investigated by ICP-AES, SEM, optical microscope, brinell hardness tester, universal testing machine. The test results that one reason is substandard products of this batch hoop. The composition of chemical elements and mechanical properties is fails to comply with applicable standards prescribed and the casting defects are found. Another reason is that the large pre-tightening force and tightens reverse order.

scholarly journals Investigation of intercritical heat treatment temperature effect on microstructure and mechanical properties of dual phase (DP) steel

10.30544/293 ◽  
2017 ◽  
Vol 23 (2) ◽  
pp. 143-152
Author(s):  
Mohammad Davari ◽  
Mehdi Mansouri Hasan Abadi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Work Hardening ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Dual Phase ◽  
Work Hardening Behavior ◽  
Hardening Behavior ◽  
Heat Treated ◽  
Intercritical Heat Treatment

In the present study, the effect of intercritical heat treatment temperature on the tensile properties and work hardening behavior of ferritic-martensitic dual-phase steel have been investigated utilizing tensile test, microhardness measurement and microscopic observation. Plain carbon steel sheet with a thickness of 2 mm was heat treated at 760, 780, 800, 820 and 840 °C intercritical temperatures. The results showed that martensite volume fraction (Vm) increases from 32 to 81%with increasing temperature from 760 to 840 °C. The mechanical properties of samples were examined by tensile and microhardness tests. The results revealed that yield strength was increased linearly with the increase in Vm, but the ultimate strength was increased up to 55% Vm and then decreased afterward. Analyzing the work hardening behavior in term of Hollomon equation showed that in samples with less than 55% Vm, the work hardening took place in one stage and the work hardening exponent increased with increasing Vm. More than one stage was observed in the work hardening behavior when Vm was increased. The results of microhardness test showed that microhardness of the martensite is decreased by increase in heat treatment temperature while the ferrite microhardness is nearly constant for all heat-treated samples.

Influence of Heat Treatment on Lithium Orthosilicate Pebbles

2012 ◽  
Vol 624 ◽  
pp. 208-211
Author(s):  
Hua Tang ◽  
Yu Tian Wang ◽  
Wei Jun Zhang ◽  
Li Shen ◽  
Yun Biao Duan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Testing Machine ◽  
Lithium Carbonate ◽  
Treatment Temperature ◽  
Particle Sizes ◽  
Vacuum Tube ◽  
Heat Treated ◽  
Tube Type ◽  
Lithium Orthosilicate ◽  
Spraying Method

Abstract: The lithium orthosilicate pebbles was fabricated by melt spraying method with lithium carbonate (Li2CO3) and silicon dioxide (SiO2). By alter heat treatment temperature to study different particle sizes of lithium orthosilicate pebbles of strength and phase. Lithium orthosilicate pebbles which were heat treated by vacuum tube type furnace study change of phase ,by XRD to study the change of phase after the heat treatment and tested strength by universal testing machine. Heat treatment would alter strength and phase by vacuum tube type furnace.

Effect of Heat Treatment on Mechanical Properties of General Purpose Stainless Steel Archwire

2013 ◽  
Vol 746 ◽  
pp. 444-449
Author(s):  
Pornkiat Churnjitapirom ◽  
Aksarin Wasumetharatsamee ◽  
Surachai Dechkunakorn ◽  
Niwat Anuwongnukroh ◽  
Theeralaksna Suddhasthira ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Testing Machine ◽  
General Purpose ◽  
Time Duration ◽  
Offset Yield Strength ◽  
Bending Modulus ◽  
Heat Treated ◽  
Point Bend

Stainless steel has been used for orthodontic application and its properties have been continuously improved. The present study compares the mechanical properties of general purpose stainless steel archwire after heat treatment with commercial heat and non-heat treated stainless steel archwires (Highland, USA). The six parameters compared included: 1) maximum strength (MPa) 2) bending modulus (GPa) 3) bending stiffness (N/mm) 4) 0.1 offset bending force (N) 5) 0.2% offset yield strength (MPa) and 6) springback. The temperatures of heat treatment were 200°C, 250°C, 300°C and 350°C at various time duration of 10, 20 and 30 minutes. Fifteen specimens were used for each of the 12 temperature/time settings to evaluate each parameter. An Instron Universal Testing Machine was used for the three-point bend testing and the diameters were measured by a micrometer. Of all 12 settings it was found that for the condition, 300°C at 10 min and 300°C at 20 min the mechanical properties were closest to the commercial (Highland, heat-treated) stainless steel archwire and appropriate for used in clinic.

Comparative Study on the Properties of CuCoBe Alloy and CuNiCoBe Alloy

2014 ◽  
Vol 988 ◽  
pp. 145-150
Author(s):  
Jian Chen ◽  
Ming Zhang ◽  
Dong Yang ◽  
Huan Liang
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Treatment Temperature ◽  
Solution Treatment Temperature ◽  
Solid Solution Treatment ◽  
Heat Treated ◽  
Melting Technique ◽  
Different Temperatures

CuNiCoBe alloy and CuCoBe alloy were cast by the vacuum inductive melting technique, and were heat treated under certain parameters. By using optical microscope, sclerometer and conductivity meter, the properties of two alloys were investigated after heat treatment. Experimental results show that the process of 980 °C for solid solution and three hours of aging at 450 °C is the best heat treatment for CuCoBe alloy, while 960 °C is the best solid solution treatment temperature for CuNiCoBe alloy with the same aging measures. Ni is beneficial to improve the hardness and conductivity of alloys, and CuNiCoBe alloy has better strength, hardness and conductivity than CuCoBe alloy at different temperatures, and two alloys all have a conductivity mutation increase near 450 °C. CuNiCoBe alloy and CuCoBe alloy soften respectively at 464 °C and 471 °C.

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.

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.

Heat Treatment, Mechanical Properties and Microstructure of T-Joint Steel Arc Welded

2018 ◽  
Vol 876 ◽  
pp. 36-40
Author(s):  
Yustiasih Purwaningrum ◽  
Dwi Darmawan ◽  
Panji Lukman Tirta Kusuma
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Weld Metal ◽  
Testing Machine ◽  
Optical Microscope ◽  
Heat Treatments ◽  
Tensile Testing Machine ◽  
Weld Metals ◽  
Quenching Process

Heat treatment of T-Joint’s steel arc welded are performed are investigated in this research. The heat treatment process that used were annealing and quenching. The microstructure was investigated by optical microscope. The mechanical behavior of the samples was investigated using universal tensile testing machine for tensile test and Microvickers hardness method for hardness testing. The microstructure of welding zone of welding metals with various heat treatments is grain boundary ferrite, Widmanstatten ferrite and acicular ferrite. The weld metal with quenching treatment has a highest tensile strength with tensile strength 197.97 Mpa. The quenching process increases the tensile strength by 49.58 %. The distortion value in weld metal without heat treatment, quenching and annealing is 0.11mm; 0.04 mm and 0.08 mm respectively. The hardness number of weld metals with quenching process have a highest number base metal, HAZ and weld metals. Results showed that the mechanical properties of T-joints steel arc welded can be improved by various heat treatments.

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