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oa Strengthening Platinum-Palladium-Rhodium Alloys by Ruthenium and Cerium Additions
Effects on Mechanical Properties at Room and High Temperature
- Source: Platinum Metals Review, Volume 47, Issue 3, Jul 2003, p. 111 - 119
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- 01 Jan 2003
Abstract
The effects of cerium and ruthenium additions on the mechanical properties of Pt-15 Pd-3.5 Rh alloy (wt.%) at ambient and high temperature are examined. The mechanical properties of the alloy were improved by adding cerium (≤ wt.%) or ruthenium (≤ 0.5 wt.%) solute, with the cerium additions giving a better strengthening effect. Higher concentrations of cerium and ruthenium did not visibly increase the strength properties of the Pt-15Pd-3.5Rh alloy and even reduced some of the mechanical properties at high temperature. Increasing the palladium content in the Pt-Pd-Rh alloy could enhance the alloy strengths at room temperature but damaged the mechanical properties at high temperatures. Observations of the morphologies of fracture sections of alloy samples after creep-rupture tests at high temperature showed ductile fracture for alloys with lower contents of palladium, cerium or ruthenium and brittle fracture for alloys with higher contents ofpalladium, cerium or ruthenium. The different strengthening mechanisms of palladium, cerium and ruthenium additions to Pt-15Pd-3.5Rh alloy are discussed.