Effect of gold addition on the microstructure, mechanical properties and corrosion behavior of Ti alloys

We performed a systematic investigation of the Ti–xAu (x?=?5, 10, 15, 20, and 40?wt%) alloys to assess the effect of addition of element Au on the microstructure, mechanical properties, and corrosion behavior of commercially pure titanium (cp-Ti). The phase and microstructure were characterized using X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the Ti–xAu alloys containing up to 15?wt% Au showed a hexagonal close-packed α-Ti structure, whereas the Ti–xAu alloys containing more than 20?wt% Au were mainly composed of the α-Ti phase and Ti₃Au intermetallic phase. We also investigated the effect of alloying element Au on the mechanical properties (including Vickers hardness and modulus) and corrosion behavior of Ti–xAu binary alloys. The addition of gold to Ti improved its hardness. Electrochemical results showed that the Ti–xAu alloys exhibited improved corrosion resistance than cp-Ti.