An Investigation on TiNi Intermetallic Produced by Electric Current Activated Sintering

Ergin, Nuri; Özdemir, Ö.

doi:10.12693/aphyspola.123.248

Cited by 11 publications

(8 citation statements)

References 9 publications

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“…The precipitates can resist the movement of dislocation and the strength is then improved. 20) As the load increases, micro-voids gradually grow and coalesce, and eventually fracture. In general, this mode of fracture is called the dimple rupture.…”

Section: Effect Of Nbc Content and Sintering Temperature On Microstrumentioning

confidence: 99%

Characteristics and Properties of Ti-8Mo-6Cr Alloys with Added NbC Powders through the Vacuum Sintering Process at Various Temperatures

Huang¹,

Chang

Wang

2017

Mater. Trans.

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In this study, three different powders are mixed and used to produce Ti-8Mo-6Cr-xNbC alloys of three different proportions: Ti-8Mo-6Cr-1NbC, Ti-8Mo-6Cr-3NbC and Ti-8Mo-6Cr-5NbC. The Ti-8Mo-6Cr-xNbC alloys simultaneously undergo a vacuum sintering process at temperatures of 1250, 1275 and 1300 C, respectively. The experimental results show that the lowest apparent porosity (0.1%) and highest hardness (66.5 HRA) of the Ti-8Mo-6Cr-1NbC alloys are acquired after sintering at 1300 C for 1 h. However, the transverse rupture strength (TRS) values of the Ti-8Mo-6Cr-1NbC alloys sintered at 1300 C display an obvious decrease as a result of the grain-coarsening phenomenon. Due to the TiC precipitates, grain re nement and a lower porosity appear in the 1250 C-sintered Ti-8Mo-6Cr-1NbC alloys, with the TRS showing an obvious increase (as compared with Ti-8Mo-6Cr, the TRS value increases from 1333 to 1532 MPa). These alloys also have the lowest corrosion current (I corr was 1.47 × 10 −5 A·cm −2 ) and highest polarization resistance (R P was 3.61 × 10 3 Ω·cm 2 ) in 1M H 2 SO 4 solutions. These results con rm that the Ti-8Mo-6Cr-1NbC alloys sintered at 1250 C possess the suitable mechanical properties and optimal corrosion resistance. [

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Section: Effect Of Nbc Content and Sintering Temperature On Microstrumentioning

confidence: 99%

Characteristics and Properties of Ti-8Mo-6Cr Alloys with Added NbC Powders through the Vacuum Sintering Process at Various Temperatures

Huang¹,

Chang

Wang

2017

Mater. Trans.

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“…If the precipitates can resist the movement of dislocation, then the strength is improved. 21) As the load increases, micro-voids gradually grow and coalesce and eventually fracture. This mode of fracture is called dimple rupture.…”

Section: Effect Of Ni Content and Sintering Temperature On Mechanicalmentioning

confidence: 99%

Change in Microstructure, Mechanical Strength and Corrosion Resistance of Ti-8Mo-xNi Alloys through Various Sintering Temperatures

et al. 2016

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In this study, three different powders are mixed and used to produce Ti-8Mo-xNi alloys in three different proportions: Ti-8Mo-4Ni, Ti8Mo-6Ni and Ti-8Mo-8Ni. The Ti-Mo-Ni alloys simultaneously undergo various vacuum sintering temperatures of 1125, 1150, 1175 and 1200 C, respectively. The experimental results show that the Ti-8Mo-8Ni alloys acquire a higher sintering density (98.9%) and hardness (52.1 HRC) after sintering at 1175 C for 1 h. However, due to the grain growth and increased amount of nickel in the Ti-8Mo-8Ni alloys, the transverse rupture strength (TRS) shows an obvious decrease (as compared with Ti-8Mo-6Ni, the TRS value decreasing from 1177 to 685 MPa). Consequently, the suitable Ni content of the Ti-8Mo-6Ni alloys which proves advantageous to the TRS results from the uniform distribution of the TiNi intermetallic compound precipitates within the β matrix. The sintered Ti-8Mo-8Ni alloys also possess the lowest corrosion current (I corr = 1.87 × 10 −7 A·cm −2) and highest polarization resistance (56084 Ω·cm 2 ) in 3.5 mass% NaCl solutions. This result con rms that sintered Ti-8Mo-8Ni alloys effectively improve corrosion resistance.

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“…1 Intermetallic compounds are promising materials for structural and non-structural high-temperature applications (heat resistance, corrosion resistance, electronic devices, magnets, super conductors). 2,3 Especially NiTi alloys are some of the most technologically important shape-memory alloys 4,5 which find extensive applications in the mechanical, medical, electronic, chemical and aerospace industries due to their excellent shape-memory effect, high erosion resistance, high damping capacity and biocompatibility. These properties make them suitable candidates for various engineering applications.…”

Section: Introductionmentioning

confidence: 99%

“…These properties make them suitable candidates for various engineering applications. [2][3][4][5][6][7] Nickel titanium is a near-equiatomic intermetallic exhibiting distinctive and desirable thermo-mechanical properties, namely, the thermal shape-memory effect and super elasticity. 8 Up to now, a number of processes including self-propagating high-temperature synthesis (SHS), thermal explosion, laser-melting deposition, casting and mechanical alloying techniques 2,5,9,10 have been used for manufacturing ýntermetallics.…”

Section: Introductionmentioning

confidence: 99%

Effect of electric current on the production of NiTi intermetallics via electric-current-activated sintering

Yener¹

2015

Mater. Tehnol.

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This study focuses on investigating the fabrication of in-situ intermetallic NiTi composites from a powder mixture containing the mass fractions 50 % nickel powder and 50 % titanium powder. The elemental powders were mixed in the stoichiometric ratio corresponding to the NiTi intermetallic molar proportion of 1 : 1, ball-milled and uniaxially compressed under a pressure of 170 MPa. Sintering was then carried out for 15 min in a steel mold using the electric-current-activated sintering method. Electric-current values of 1000 A, 1300 A and 2000 A were used for the sintering while keeping the voltage in the range of 0.9 V to 1.2 V. The phases in the samples were analyzed with XRD and their Vickers hardness was measured as (701 ± 166) HV0.05. Energy dispersive X-ray spectroscopy carried out with a scanning electron microscope (SEM-EDS) showed that the microstructures of the samples consist of different phases such as Ti, Ni2Ti3, NiTi2, Ni3Ti and TiO2 as a function of electric current. The XRD analysis also supported the SEM-EDS results. The nano-indentation technique was used to determine the elastic modulus of different phases. Keywords: NiTi intermetallics, electric-current-activated sintering (ECAS), nano-indentation Ta {tudija je usmerjena v preiskavo in situ izdelave intermetalnega NiTi-kompozita iz me{anice prahov z masnima dele`ema 50 % niklja v prahu in 50 % titana v prahu. Obe vrsti prahu sta bili zme{ani v stehiometri~nem razmerju, ki ustreza molskemu razmerju NiTi 1 : 1, zmleti v kroglastem mlinu in enoosno stisnjeni pri tlaku 170 MPa. Petnajstminutno sintranje je bilo izvr{eno v jeklenem kalupu s sintranjem, aktiviranim z elektri~nim tokom. Pri sintranju so bili uporabljeni elektri~ni tokovi 1000 A, 1300 A in 2000 A, medtem ko je bila napetost v obmo~ju med 0,9 V in 1,2 V. Faze v vzorcih so bile dolo~ene z rentgenom (XRD) in izmerjena je bila trdota po Vickersu (701 ± 166) HV0,05. Energijska disperzijska rentgenska spektroskopija (EDS), izvr{ena na vrsti~nem elektronskem mikroskopu (SEM-EDS), je pokazala, da je mikrostruktura vzorcev sestavljena iz razli~nih faz, kot so Ti, Ni2Ti3, NiTi2, Ni3Ti in TiO2, odvisno od elektri~nega toka. XRD-analiza je podprla rezultate, dobljene s SEM-EDS. Elasti~ni modul razli~nih faz je bil dolo~en z nanovtiski. Klju~ne besede: intermetalna zlitina NiTi, sintranje, aktivirano z elektri~nim tokom (ECAS), nanovtiski

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An Investigation on TiNi Intermetallic Produced by Electric Current Activated Sintering

Cited by 11 publications

References 9 publications

Characteristics and Properties of Ti-8Mo-6Cr Alloys with Added NbC Powders through the Vacuum Sintering Process at Various Temperatures

Characteristics and Properties of Ti-8Mo-6Cr Alloys with Added NbC Powders through the Vacuum Sintering Process at Various Temperatures

Change in Microstructure, Mechanical Strength and Corrosion Resistance of Ti-8Mo-xNi Alloys through Various Sintering Temperatures

Effect of electric current on the production of NiTi intermetallics via electric-current-activated sintering

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