High Temperature Strengthening Mechanisms in the Alloy Platinum- 5% Rhodium DPH

Abstract

To improve the high temperature properties, platinum can be hardened by solid solution and/or oxide parti-cles. The investigated alloy, dispersion hardened plati-num-5% rhodium (Pt-5%Rh DPH), was produced via melting and subsequent annealing of the semi-fi nished product in order to obtain an oxide particle dispersion. Despite the relatively large oxide particles formed in this process, the creep strength is much higher in com-parison to conventional Pt-5%Rh. The aim of this paper is to study the strengthening mechanisms in the alloy Pt-5%Rh DPH by transmission and scanning electron microscopy. The size distribution of oxide particles shows a bimodal distribution, and the average oxide particle diameter is 315 nm for particles larger than 150 nm. For particles between 25 nm and 150 nm the average diameter is 49 nm. The size ranges of oxide par-ticles are not substantially affected by high temperature creep deformation, but particles of