Mechanical alloying of NiTi alloys with Ag and Cu nanoparticles: synthesis and characterization

Abstract This study investigates the mechanical alloying of silver (Ag) and copper (Cu) nanoparticles with pre-alloyed micro-sized NiTi powders and the characterization of the produced powders both as their powder and sintered forms. Nanocomposite powders with constant Cu content (2.5 wt%) and a variable Ag content (0.5 to 2.5 wt%) were mechanically alloyed in a planetary ball mill and analyzed by XRD, FESEM and EDS methods. The production process involved the dispersion of Cu and Ag nanoparticles in alcohol to obtain a homogeneous distribution, followed by mechanical alloying. The alloyed NiTiCuAg powders obtained by mechanical alloying were compacted using a hydraulic press and subjected to sintering at 1100 °C. Vickers hardness, microhardness and compressive strength tests were performed on the sintered samples. The fracture toughness was determined using Vickers indentation under a 50 kg load. The results showed that the sample containing 2.5% Cu and 1.0% Ag in alloys with different compositions had optimal mechanical properties. The increase of Ag ratio beyond 1.5% causes weakness in mechanical properties. Overall, the addition of Cu and Ag nanoparticles to the NiTi matrix improved the mechanical properties up to a certain Ag content. Based on this, future studies will be followed to investigate the antibacterial properties of NiTi(Cu 2.5 , Ag 1.0 ) nanocomposite alloys.