Microstructure and strength of weldment in Pt20Rh alloys dispersion-strengthened by ZrO2 particles

Abstract

Abstract A series of Pt20Rh alloys dispersion-strengthened by different volume fractions of ZrO2 particles have been prepared by internal oxidation of Pt20Rh powder followed by consolidation and hot forging. The alloys were cold rolled to sheets, followed by annealing. The effects of welding on the microstructure and mechanical properties were also investigated. The microstructure of the rolled sheets showed a lamellar structure and the yield stress was significantly increased with increasing volume fraction of dispersion particles. After welding, the yield stress at room temperature was almost unchanged, although a small decrease was observed at 1000 °C. However, the work hardening capacity and ultimate tensile stress were significantly reduced in the welded sample due to grain coarsening and to increased pore density in the fusion zone.