Metal injection molding of shape memory alloys using prealloyed NiTi powders

Schöller, E.; Krone, L.; Bram, Martin; Buchkremer, Hans Peter; Ståaver, D.

doi:10.1007/s10853-005-2819-5

Cited by 35 publications

(14 citation statements)

References 16 publications

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“…[8] To overcome the problems related to the melting process and subsequent conventional machining, alternate production routes have been developed for nitinol. Powder metallurgical methods like hot-isostatic pressing (HIP) [9][10][11][12] metal injection molding, [10,13] self-propagating high-temperature synthesis (SHS), [14,15] and normal sintering [8,16] have been investigated. Metal injection molding is a combination of polymer injection molding and powder metallurgy.…”

Section: Introductionmentioning

confidence: 99%

“…Metal injection molding is a combination of polymer injection molding and powder metallurgy. [13] Metal powder is mixed with a binder to obtain a feedstock for the injection molding devices to form green bodies, which are sintered to obtain final components. [13] The binder used, however, acts as a direct source of impurity, which is detrimental to the final properties of nitinol.…”

Section: Introductionmentioning

confidence: 99%

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In Situ Synthesis and Characterization of Shape Memory Alloy Nitinol by Laser Direct Deposition

Halani

Shin

2011

Metall Mater Trans A

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Nitinol is well known for its unique shape-memory and super-elastic properties along with its excellent biomechanical compatibility and corrosion resistance. In this study, a laser direct deposition technique was explored to synthesize high-quality, near-net-shape nitinol components directly from elemental nickel and titanium powders as opposed to using expensive prealloyed nitinol powder. The systematic characterization of samples was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Transformation temperatures were obtained using differential scanning calorimetry (DSC). With an optimum ratio of nickel and titanium powder mixture, optimal laser parameters, and post-heat treatment, samples with homogeneous and nearly fully dense NiTi phase were synthesized with less unwanted secondary phases occupying less than 3.2 pct volume fraction. Furthermore, these results were compared with those obtained for samples deposited using prealloyed nitinol powder. This technique offers maximum flexibility and cost benefit in the manufacturability of near-net-shape nitinol components.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In Situ Synthesis and Characterization of Shape Memory Alloy Nitinol by Laser Direct Deposition

Halani

Shin

2011

Metall Mater Trans A

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“…[89] with permission. [127][128][129][130][131][132] system. Agar provides the ''setting'' function for the molded part.…”

Section: A Non-gelation Based Synthetic Polymersmentioning

confidence: 99%

Development and Design of Binder Systems for Titanium Metal Injection Molding: An Overview

Wen

Cao

Gabbitas

et al. 2012

Metall Mater Trans A

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Titanium metal injection molding (Ti-MIM) has been practiced since the late 1980s. Logically, the Ti-MIM practice follows the similar processes developed for the antecedent materials such as stainless steel and ceramics. Although Ti-MIM is a favorite research topic today, the issue of convincing the designers to use Ti injection-molded parts still exists. This is mainly because of the concern about contamination which seems unavoidable during the Ti-MIM process. Much information about the binder formulation, powder requirements, debinding, and sintering is available in the literature. There are several powder vendors and feedstock suppliers. However, most of the binders in the feedstock are proprietarily protected. The disclosed information on the binders used for formulating powder feedstock is very limited, which in turn discourages their adoption by engineering designers. This overview intends to discuss some of major binder systems for Ti-MIM available in the literature. It serves to provide a guideline for the Ti-MIM practitioners to choose a suitable powder feedstock.

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“…To fulfil this requirement, extensive work was oriented towards the pre-alloyed powders method [4,5,[9][10][11]. Tensile test samples, bone staples, pipe connectors were fabricated by metal injection moulding from pre-alloyed powders [10,12]. Densities ranging from 90 to 97% and tensile strengths of up to 1000 MPa were reported [5,11].…”

Section: Introductionmentioning

confidence: 99%

“…In Fig. 9, a shoulder close to the main TiNi peak is observed, which indicates the first stage of the formation Ni 4 Ti 3 precipitates [12]. Indeed the peak is not fully developed, as after standard ageing treatments [17].…”

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confidence: 99%

Metal Injection Moulding of Superelastic TiNi Parts

Bidaux

Hidalgo

Girard

et al. 2016

KEM

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Abstract. TiNi shape-memory properties are successfully used today for the fabrication of various technical devices. The limited machinability and high cost of TiNi encourage the use of near-net shape production techniques such as metal injection moulding. In this work TiNi alloys tensile test specimens are produced by metal injection moulding from pre-alloyed powders. A binder based on a mixture of polyethylene, paraffin wax and stearic acid is used. Parts with a density of about 96.6% of theoretical density are obtained. Scanning electron microscopy coupled with EDX measurements reveals a microstructure consisting of a TiNi matrix with small Ti 4 Ni 2 O x and TiC inclusions. DSC and X-ray diffraction observations indicate the presence of additional Ni 4 Ti 3 precipitates. The parts exhibit full superelasticity at room temperature even for strains of up to 4%, without the need for additional thermal post-treatments. Ultimate tensile strengths up to 980 MPa are obtained.

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Metal injection molding of shape memory alloys using prealloyed NiTi powders

Cited by 35 publications

References 16 publications

In Situ Synthesis and Characterization of Shape Memory Alloy Nitinol by Laser Direct Deposition

In Situ Synthesis and Characterization of Shape Memory Alloy Nitinol by Laser Direct Deposition

Development and Design of Binder Systems for Titanium Metal Injection Molding: An Overview

Metal Injection Moulding of Superelastic TiNi Parts

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