Microstructures and Properties of Ti-25Nb-15Zr Alloy for Spectacle Frame

2017 ◽  
Vol 727 ◽  
pp. 191-195
Author(s):  
Xi Qun Ma ◽  
Zhen Tao Yu ◽  
Han Yuan Liu ◽  
Jun Cheng ◽  
Jin Long Niu ◽  
...  

Mechanical properties and microstructures of a new β Ti-25Nb-15Zr alloy for spectacle frame were studied. The results show that the optimum cold rotary swaging reduction of the alloy is between 50% and 70%. The wire of 3mm in diameter exhibited an equiaxed microstructure consisting only β single phase and fine grain with less than 10mm size when the alloy is heat treated at 1003K for 1.8Ks. While it has good shape memory property, and the maximum complete recovery strain was up to 3% at room temperature. At the same time, the flattened frame legs were solution-treated to improve their elastic behavior, so the residual strain was completely or partly recovered due to transformation of the microstructure.

Author(s):  
Michael M. Kersker ◽  
E. A. Aigeltinger ◽  
J. J. IIren

Ni-rich alloys based on approximate ternary composition Ni-8Mo-15A1 (at%) are presently under investigation in an attempt to study the contribution, if any, of the profusion of Mo-rich NixMo metastable compounds that these alloys contain to their excellent mechanical properties. One of the alloys containing metastable NixMo precipitates is RSR 197 of composition Ni-8.96Mo-15.06A1-1.98Ta-.015Yt. The alloy was prepared at Pratt and Whitney Government Products Division, West Palm Beach, Florida, from rapidly solidified powder. The powder was canned under inert conditions and extruded as rod at 1315°C. The as-extruded rod, after air cooling, was solution treated at 1315°C for two hours, air cooled, and heat treated for one hour at 815°C, followed again by air cooling.


2021 ◽  
Vol 11 (6) ◽  
pp. 2547 ◽  
Author(s):  
Carlo Prati ◽  
João Paulo Mendes Tribst ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Alexandre Luiz Souto Borges ◽  
Maurizio Ventre ◽  
...  

The aim of the present investigation was to calculate the stress distribution generated in the root dentine canal during mechanical rotation of five different NiTi endodontic instruments by means of a finite element analysis (FEA). Two conventional alloy NiTi instruments F360 25/04 and F6 Skytaper 25/06, in comparison to three heat treated alloys NiTI Hyflex CM 25/04, Protaper Next 25/06 and One Curve 25/06 were considered and analyzed. The instruments’ flexibility (reaction force) and geometrical features (cross section, conicity) were previously investigated. For each instrument, dentine root canals with two different elastic moduli(18 and 42 GPa) were simulated with defined apical ratios. Ten different CAD instrument models were created and their mechanical behaviors were analyzed by a 3D-FEA. Static structural analyses were performed with a non-failure condition, since a linear elastic behavior was assumed for all components. All the instruments generated a stress area concentration in correspondence to the root canal curvature at approx. 7 mm from the apex. The maximum values were found when instruments were analyzed in the highest elastic modulus dentine canal. Strain and von Mises stress patterns showed a higher concentration in the first part of curved radius of all the instruments. Conventional Ni-Ti endodontic instruments demonstrated higher stress magnitudes, regardless of the conicity of 4% and 6%, and they showed the highest von Mises stress values in sound, as well as in mineralized dentine canals. Heat-treated endodontic instruments with higher flexibility values showed a reduced stress concentration map. Hyflex CM 25/04 displayed the lowest von Mises stress values of, respectively, 35.73 and 44.30 GPa for sound and mineralized dentine. The mechanical behavior of all rotary endodontic instruments was influenced by the different elastic moduli and by the dentine canal rigidity.


2016 ◽  
Vol 97 ◽  
pp. 141-146 ◽  
Author(s):  
Taywin Buasri ◽  
Hyunbo Shim ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Kenji Goto ◽  
...  

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.


2012 ◽  
Vol 622-623 ◽  
pp. 366-369 ◽  
Author(s):  
Rizwan Abdul Rahman Rashid ◽  
Shou Jin Sun ◽  
Gui Wang ◽  
Matthew Simon Dargusch

Machining of Ti25Nb3Mo3Zr2Sn beta titanium alloy is carried out under two different heat treatments, solution treated, and solution treated and aged conditions. The chips formed after machining were cold mounted, polished and etched to reveal their microstructures. Different chip parameters such as average chip thickness, shear angle, undeformed chip length, and distance between serrations were measured and reported for both the heat treated samples for a wide range of cutting speeds, ranging from 5 m/min to 175 m/min. The results obtained were explained in terms of the heat treatment (hardness) of the samples and the cutting speeds.


CORROSION ◽  
1972 ◽  
Vol 28 (9) ◽  
pp. 331-336 ◽  
Author(s):  
B. L. TROUT ◽  
R. D. DANIELS

Abstract The anodic polarization characteristics of Inconel X-750 Alloy in two heat treated conditions, (1) solution treated and (2) solution treated and aged, were examined for sensitivity to temperature and to chloride ion concentration. The effects of microstructure and environment on the anodic passivation behavior of this alloy are correlated and discussed.


1996 ◽  
Vol 457 ◽  
Author(s):  
S. M. Pickard ◽  
A. K. Ghosh

ABSTRACTA rapid physical vapor deposition process (PVD) utilizing a high speed rotating substrate and small substrate-to-source spacing has been used to produce bulk sheet of Ti-Al alloys in the compositional range Ti-12% Al to Ti-75% Al1 at a rate of 1–3 μm/minute. Microstructural architectures produced by the method comprise of either fully homogenous phase mixtures of nano-grains, or nanolaminated material, depending on the substrate rotational rate, with lower rotational rate producing a layered microstructure. Defect populations within the as-deposited material are characterized by TEM and SEM, and hot pressing consolidation of the as-deposited material, which retains a grain size < 1000 nm, has been investigated. While indentation hardness of α2+γ(2 phase) alloys exceeded 7 GPa, brittle failure occurred in the elastic regime at nominally lower tensile stress than that for conventionally produced alloys containing Nb and Cr as solute elements. α2+γ alloys can exhibit tensile elongations of more than 100% at 850°C with retention of fine grain size. Elevated temperature failure occurs by the formation of voids in regions of compositional variability in the composite where single phase α2-Ti3Al structure was present.


2010 ◽  
Vol 654-656 ◽  
pp. 2176-2179 ◽  
Author(s):  
Shingo Mineta ◽  
Alfirano ◽  
Shigenobu Namba ◽  
Takashi Yoneda ◽  
Kyosuke Ueda ◽  
...  

The phase and morphology of precipitates in heat-treated Co-28Cr-6Mo-xC (x = 0.12, 0.15, 0.25, and 0.35mass%) alloys were investigated. The as-cast alloys were solution-treated in the temperature range of 1473 to 1623 K for 0 to 43.2 ks. Complete precipitate dissolution was observed in all four alloys, each of which had different carbon contents. The holding time for complete dissolution was greater for alloys with greater carbon content. The curve representing the boundary between the complete- and incomplete-dissolution conditions for each alloy is C shaped. Under the incomplete precipitate dissolution conditions of the Co-28Cr-6Mo-0.25C alloy, an M23C6 type carbide and a π-phase (M2T3X type carbide with β-Mn structure) were observed at 1548 to 1623 K, and starlike precipitates with a stripe pattern and with a dense appearance were both observed; the former comprised the M23C6 type carbide + γ-phase, and the latter was the π-phase. In contrast, only a blocky-dense M23C6 type carbide was observed at 1473 to 1523 K.


2008 ◽  
Vol 368-372 ◽  
pp. 754-757
Author(s):  
Hasan Gocmez ◽  
Hirotaka Fujimori

The citrate gel method, similar to the polymerized complex method, was used to synthesize homogenous tetragonal zirconia at 800oC and 1000oC. Nanocrystalline tetragonal single phase has been fully stabilized with 3, 7, 10 mol% CaO and 10, 15 mol% MgO at 800oC, respectively. In addition, the XRD analysis showed the absence of monoclinic phase after addition of 7 and 10 mol% CaO into zirconia-based solid solutions, which have been fully stabilized both 800oC and 1000oC. The crystallite sizes of the t-ZrO2 with 3, 7 and 10 mol% CaO at 1000oC were 32, 28 and 29nm, respectively. For ZrO2- x mol% MgO (x=3, 10, 15) solid solution, the crystallite sizes of samples at 800oC were less than 29nm, however it was increased up to 69nm at 1000oC. The prepared gel and subsequent heat-treated powders were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM) to get detail information regarding to differentiation of polymorphs of zirconia as well as formation of powders.


2013 ◽  
Vol 549 ◽  
pp. 164-171 ◽  
Author(s):  
Amirahmad Mohammadi ◽  
Hans Vanhove ◽  
Albert van Bael ◽  
Joost R. Duflou

The influence of thermal pre-treatment on the formability of a precipitation-hardening aluminium alloy AA-2024 has been studied for three different heat treatment conditions: annealed (O-temper), solution treated and quenched (W-temper) and solution heat treated, quenched and then cold worked (T-temper).The maximum draw angle has been determined and the geometrical accuracy of specific SPIF formed parts has been compared. It is found that the maximum forming angles of the blank formed in O-temper and W-temper conditions show a respective 41% and 32% increase to those of the T-temper condition (initial blank).The hardness of the material reduces significantly after annealing, while SPIF parts formed from W-temper blanks regain their initial hardness after natural aging.


2016 ◽  
Vol 703 ◽  
pp. 100-105
Author(s):  
Yue Ming Shi

A combination study of magnetic and magnetostrictive properties in directionally cast and differently heat-treated Fe-20Ga(at.%) samples has been carried out at room temperature. Slow cooling leads to an increase in the occupation of [200] easy magnetic axes; however, a structural ordering of Ga atoms into a metastable D03 phase decreasesthe saturation magnetostriction (λs) and the saturation magnetization (Ms), and increases coercivity (Hc).Our results confirm the contribution of D03 ordering to magnetic and magnetostrictive properties due to their pinning effects against magnetic domain wall motions. As compared to slow cooling, water quenching suppresses the formation of metastable (D03) or stable (L12) ordered phases and preserves the A2 single phase structure down to room temperature, leading to enhanced magnetostriction and magnetization.


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