DEFORMATION OF AG 1.2 AT-PERCENT MG

Mechanical properties of Ag/1.2 at.% Mg were measured at room temperat ure in air and at 900 degrees C in Ar or O-2. Exposure to O-2 at 900 d egrees C induced formation of MgO precipitates, which hardened the mat erial and decreased its ductility substantially at both temperatures, At room temperature, oxidation increased the yield strength by a facto r of similar to 8 and the stiffness by similar to 16%. At 900 degrees C and strain rates of 3 x 10(-6) to 10(-4) s(-1), deformation was stro ngly dependent on atmosphere: in Ar, the alloy deformed by dislocation motion and underwent dynamic recrystallization; in O-2, the yield str ess increased by a factor of similar to 10, but the specimens fracture d after limited plasticity.