Mechanical behaviour of NiTi parts prepared by powder metallurgical methods

Krone, L.; Schüller, E.; Bram, Martin; Hamed, O.A.; Buchkremer, Hans Peter; Stöver, D.

doi:10.1016/j.msea.2003.10.345

Cited by 83 publications

(45 citation statements)

References 9 publications

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“…3 As an alternative to conventional production methods for the NiTi alloy (vacuum induction melting and vacuum arc remelting), powder-metallurgy processes starting from pre-alloyed NiTi powder have been developed. 4 An alternative powder-metallurgy process for the production of ceramics or intermetallics is reaction synthesis. In this process, the compressed mixture of elemental powders is transformed to intermetallic, thermally activated exothermic reactions.…”

Section: Introductionmentioning

confidence: 99%

Powder-metallurgy preparation of NiTi shape-memory alloy using mechanical alloying and spark-plasma sintering

Novák¹,

Moravec²,

Vojtěch³

et al. 2017

Mater. Tehnol.

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In this work a combination of mechanical alloying and spark-plasma sintering was tested as a promising route for the preparation of a nanocrystalline NiTi shape-memory alloy. The mechanism of mechanical alloying was investigated. Results revealed that the Ti2Ni phase forms preferentially, being followed by the NiTi phase (austenite B2 structure) and a small amount of Ni3Ti. During spark-plasma sintering, only minor changes occurred in the phase composition, i.e., precipitation of the Ni4Ti3 phase and the partial transformation of NiTi to monoclinic martensite. The selected technology leads to a very high compression strength (approx. 2300 MPa), but also high brittleness. Keywords: mechanical alloying, spark plasma sintering, NiTi, shape memory alloy V delu je bila preizku{ena kombinacija mehanskega legiranja in sintranja z iskrilno plazmo, ki predstavlja obetajo~na~in za pripravo nanokristalne NiTi spominske zlitine. Preiskovan je bil mehanizem mehanskega legiranja. Rezultati so odkrili, da se najprej tvori faza Ti2Ni, ki ji sledi faza NiTi (avstenitna B2 struktura) in manj{i dele`Ni3Ti. Med sintranjem z iskrilno plazmo se pojavijo le manj{e razlike v sestavi faz, to je izlo~anje faze Ni4Ti3 in delna pretvorba NiTi v monoklinski martenzit. Izbrana tehnologija povzro~i veliko tla~no trdnost (okoli 2300 MPa) in tudi veliko krhkost materiala. Klju~ne besede: mehansko legiranje, sintranje z iskrilno plazmo, NiTi, zlitina z oblikovnim spominom

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Section: Introductionmentioning

confidence: 99%

Powder-metallurgy preparation of NiTi shape-memory alloy using mechanical alloying and spark-plasma sintering

Novák¹,

Moravec²,

Vojtěch³

et al. 2017

Mater. Tehnol.

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“…[10]. The mixed powders have been hot-isostatically-pressed at pressure of 100 MPa for 3h at temperature of 1065°C [5,11]. The HIP-processed samples were mechanically polished to a 2000 grit SiC finish.…”

Section: Methodsmentioning

confidence: 99%

Challenges of Using Elemental Nickel and Titanium Powders for the Fabrication of Monolithic NiTi Parts

Farvizi¹

2017

Archives of Metallurgy and Materials

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Due to its interesting properties and wide applications in different industries, fabrication of monolithic NiTi with cost-effective methods is an important and attractive issue. One of the economic ways to fabricate NiTi is employing elemental nickel and titanium powders. In this study, effects of using elemental powders as a precursor on the microstructure and mechanical properties of HIP-consolidated NiTi samples will be explored. The result of XRD analysis showed that after HIP process an interwoven structure which consists of NiTi 2 , Ni 3 Ti and B2-B19′ NiTi evolves. The formation of NiTi 2 /Ni 3 Ti intermetallics is thermodynamically favored which affects different aspects of this alloy: (i) it alters martensitic transformation temperatures; (ii) restricts essential properties of this alloy such as PE and SME, (iii) increases hardness, and (iv) yields to premature fracture at small strains during tensile tests.

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“…As suggested in [18,9], for rectangular 2D unit cells with the total dimensions along the two coordinate axes 1 x , 2 x denoted by 1 2a and 2 2a , the classical periodicity conditions:…”

Section: Periodic Microstructurementioning

confidence: 99%

“…Currently, several methods are adopted for manufacturing porous SMA from elemental powders. Many porous NiTi SMA with different structures of pores have been successfully produced by sintering at elevated pressure via a hot isostatic press or metal injection molding [1], spark plasma sintering [2], combustion synthesis with a self-propagating wave [3]. The possibility of producing SMA in porous form has opened new fields of applications owing to their low-weight with high energy dissipation properties.…”

Section: Introductionmentioning

confidence: 99%

Response of porous SMA: a micromechanical study

Sepe

Marfia

Auricchio

2014

Frattura Ed Integrità Strutturale

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ABSTRACT. Lately porous shape memory alloys (SMA) have attracted great interest as low weight materials characterized by high energy dissipation capability. In the present contribution a micromechanical study of porous SMA is proposed, introducing the simplifying hypothesis of periodic distribution of voids. The mechanical response of the heterogeneous porous medium is derived by performing nonlinear finite element micromechanical analyses considering a typical repetitive unit cell made of a circular hole in a dense SMA matrix and prescribing suitable periodicity and continuity conditions. The constitutive behavior and the dissipation energy capability of the porous Nitinol are examined for several porosity levels. Numerical applications are performed in order to test the ability of the proposed procedure to well capture the overall behavior and the key features of the special heterogeneous material.

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Mechanical behaviour of NiTi parts prepared by powder metallurgical methods

Cited by 83 publications

References 9 publications

Powder-metallurgy preparation of NiTi shape-memory alloy using mechanical alloying and spark-plasma sintering

Powder-metallurgy preparation of NiTi shape-memory alloy using mechanical alloying and spark-plasma sintering

Challenges of Using Elemental Nickel and Titanium Powders for the Fabrication of Monolithic NiTi Parts

Response of porous SMA: a micromechanical study

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