Effect of Zr on microstructure and mechanical property of dispersion-strengthened Pt-20Rh

Abstract

Dispersion-strengthened Pt-20Rh was designed and prepared by powder metallurgy-internal oxidation-sintering. After rolling and annealing, the microstructures, mechanical properties at room temperature and 1000 °C were tested and analysed. Results indicate that the dispersion-strengthened Pt-20Rh alloy consists of Pt and Rh solid solution, Y₂O₃ and ZrO₂. It has a stabilised grain structure at 1000 °C. As the Zr content increases, the strengths at room temperature and high temperature are greatly improved. ZrO₂ particles can pin up and block the movement of dislocations, making it possible to enhance the strength. When Zr content is 0.3 wt-%, the room temperature and 1000 °C tensile strengths are up to their maximum, i.e. 555 and 149 MPa, respectively.