Different Deformation Behavior Between ZrO2 and Y2O3 Particles in Dispersion Strengthened Pt-20Rh Alloys

Abstract

Pt-20Rh strengthened by oxides of Zr and Y were prepared by solidification of Pt-Rh-(Zr)-Y powder which had been internally oxidized. After forging, rolling and annealing, the 1 mm plates were obtained. Then the plates from rolling-normal direction were mechanically grinded to 50-70 μm, followed by Ar+ ion milling until a hole appeared on the center of the foil to obtain samples which characterized by transmission electron microscopy (TEM), combined with thermodynamic analysis, the existence of spherical ZrO2 and Y2O3 particles was verified, Pt and Rh still existed as a form of pure metals at the same time. It was found that the deformation behavior of ZrO2 and Y2O3 particles was quite different during processing, where the former basically maintain their spherical shape and were bonded tightly to matrix, while the latter were compressed along normal direction and form two cracks on the both sides of Y2O3 particles along rolling direction. The differences in hardness and interface bonding properties of these two types of particles are supposed to be the main causes of different deformation behavior during hot forging and cold rolling.