Effect of microstructure on mechanical properties and fracture of dispersion strengthened platinum

Two types of dispersion strengthened Pt with the same weight fraction (0.5% ) of Y2O3 particles are analyzed in the paper. But the technological parame ters of their preparation by application of laboratory manufacture procedur e are different. The first material (A) has worse strength and plastic prop erties in the temperature interval from 20 to 600 degrees C. At the tempera ture 600 degrees C their properties are similar to the properties of pure P t metal. Second material (B) has very favourable strength properties up to the temperature of 700 degrees C. They are two-three times better than thos e of the material (A) and they also exceed the strength parameters of dispe rsion strengthened Pt materials used at present. In this paper the essence of different properties of both materials on the qualitative level is expla ined on the basis of microstructural and microfractografical analyses. Bett er properties of the material (B) consist in grain refining of Pt matrix, l ow porosity and its stability, higher effectiveness of dispersion strengthe ning, in thermomechanical effect and with it connected increase of dislocat ion strengthening.