A comparison of the microstructures, thermal and mechanical properties of pressed and sintered Ti–Cu, Ti–Ni and Ti–Cu–Ni alloys intended for dental applications

The effect of Ni and Cu on the α→β phase transformation temperature, possible retention of the β-phase, and mechanical properties of Ti, Ti–13Cu, Ti–4.5Ni and Ti–13Cu–4.5Ni (compositions in wt. %) alloys were investigated. The alloys were developed using the conventional uniaxial cold press and sintering technique. The thermal properties of the sintered alloys were traced by the differential scanning calorimetry (DSC) analysis. The x-ray diffraction (XRD) and electron backscatter diffraction (EBSD) analysis determined phase composition, crystal structures and grain orientations. It has emerged that the Ti–13Cu and Ti–13Cu–4.5Ni retained the β-Ti phase. The mechanical properties were evaluated under tension with Ti–13Cu and Ti–4.5Ni possessing high ultimate tensile strength (UTS) and percentage elongation (%El) than the Ti–13Cu-4.5Ni alloy. Although all the alloys have revealed the presence of porosity, its effect on mechanical properties was more on the Ti–13Cu–4.5Ni alloy. While the mechanical properties of Ti–13Cu-4.5Ni alloy were inferior due to extensive porosity, those of Ti, Ti–13Cu and Ti–4.5Ni allow them to be classified as Type 3 and Type 4 dental alloys, respectively, proving that the conventional powder metallurgy process has potential to be used as a processing technique for Ti–Cu-based dental alloys.