Production of Nitinol Wire from Elemental Nickel and Titanium Powders Through Spark Plasma Sintering and Extrusion

Abstract

This study demonstrates the production of highly dense binary NiTi by spark plasma sintering (SPS) of elemental Ni and Ti powders. The sintered billets were extruded to 0.7 mm wire for tensile testing. Excellent mechanical properties and very dense microstructures were obtained in the wires produced in this way. The material demonstrated 4% recoverable strain, 14% elongation at fracture and 630 MPa ultimate tensile stress. Furthermore, a close control of the level of impurities was also possible. This highlights the efficacy of the SPS route in production-capacity manufacture of NiTi products.

Metals for bone implants. Part 1. Powder metallurgy and implant rendering

“…In addition, structural strength may often be reduced due to incomplete sintering of the powders [100]. However, successful applications have been reported which use conventional sintering or advanced sintering techniques such as spark plasma sintering (SPS, also known as field-activated pressure-assisted synthesis, see Figure 3a) [101] for the production of dense NiTi and porous NiTi, in particular [92,101,102]. In SPS, a feedstock consisting of either a mixture of elemental powders [101] or pre-alloyed powder [102] is compacted, usually in a graphite or steel die [101].…”

Achieving biocompatible stiffness in NiTi through additive manufacturing

“…Powder metallurgical (PM) processing routes seem to provide the most attractive potential for manufacturing porous NiTi. These methods include conventional sintering (Khalifehzadeh et al, 2007;Li et al, 1998Li et al, , 1999Li et al, , 2000aZhu et al, 2005), spark plasma sintering (SPS) (Butler et al, 2011;Majkic et al, 2007;Zhao et al, 2005), self-propagating high-temperature synthesis (SHS) (Bansiddhi and Dunand, 2007;Barrabe´s et al, 2008;Chu et al, 2004;Han et al, 1997;Lagoudas and Vandygriff, 2002;Schetky and Wu, 2004), and metal injection molding (MIM) (Bram et al, , 2012Guoxin et al, 2008;Ko¨hl et al, 2008Ko¨hl et al, , 2009Ko¨hl et al, , 2011. In general, most of these methods allow for a significant reduction in stiffness by adding porosity.…”

Additive Manufacturing: An Opportunity for the Fabrication of Near-Net-Shape NiTi Implants

“…Typically, NiTi alloys have been manufactured by casting and powder metallurgy methods [82,83]. The vacuum arc remelting [84] and vacuum induction melting processes [85] are categorized as casting methods, and sintering [86], self-propagating high-temperature synthesis [87], hot isostatic pressing [88], metal injection molding [89], and spark plasma sintering [90] are used as powder metallurgy techniques to produce NiTi alloys. Generally, powder metallurgy routes can be used to fabricate porous NiTi implants [83].…”