Phase transformation temperatures for NiTi alloys prepared by powder metallurgical processes

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

“…Both pre-alloyed NiTi powder [93] as well as mixtures of elemental powders have been used [94][95][96][97]. Instead of pure Titanium powder or in addition to pure Titanium powder, also the use of TiH 2 is described in the literature.…”

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

“…2 higher SPS temperature than 900°C or pressure over 50 MPa was used, the metal would have flashed out at the punch. The density after sintering with these optimized settings was calculated to be 98.5% of the theoretical density taken as 6.5 g/cm 3 . The microstructural analysis showed that the extrusion process decreased the residual porosity and the average pore dimension, as observed in SEM, was below l lm in size.…”

“…Most production of PM-NiTi uses pre-alloyed powder that are then consolidated either by hot isostatic pressing (HIP) or metal injection molding (MIM) to form the desired near-net shape ( Ref 1,[3][4][5]. Research work using elemental powders as feedstock are inconclusive as these samples did not receive any thermo-mechanical working to fully develop their microstructures and mechanical properties ( Ref 2,[9][10][11]14,16,17).…”

PM Processing of Single-Phase NiTi Shape Memory Alloys by VPCR Process

“…One other important critical issue of the NiTi powder technological processing is to achieve final compositions close to nominal ones because any changes in nickel content of the NiTi matrix may shift the transformation temperatures in a uncontrollable manner. 19,20) In this work, it will be shown that, by using VPCR process, near-equiatomic single-phase NiTi alloys with phase transformation temperatures and latent heats close to those of reference melt-cast alloys, are obtained. Furthermore, by choosing suitable sintering parameters, the porosity rate can be controlled.…”