Investigation of characterization and sinterability of mechanically synthesized NiTi

Abstract

In this study; prealloyed NiTi powders and ball mills with 2%, 4%, 6%, 8% and 10% Zn powder ratios were subjected to mechanical milling for 60 minutes. The milled NiTi + Zn powder mixtures were pressed under 750 MPa pressurize and then sintered at 1000 degrees C for 60 minutes. In order to determine the microstructural changes in the samples which were milled, pressed and then sintered samples; SEM, EDS, DSC and XRD analyses were applied, respectively. Changes in powder morphology were observed, depending of the increasing Zn content in the NiTi + Zn powder mixtures and it was determined that the powders containing 10% Zn completely covered the surface of the NiTi powders in a homogeneous manner after milling.

Zn content in the micro structure also provided the alloy to be sintered at low temperatures by completely filling the gaps and pores after the sintering process at 1000 degrees C for 60 min. In addition, a homogenous and smooth microstructure was obtained with NiTi + 10Zn% content.