Strengthening mechanisms in aluminum containing coherent Al3Sc precipitates and incoherent Al2O3 dispersoids
نویسندگان
چکیده
Dispersion-strengthened-cast aluminum (DSC-Al), consisting of a coarse-grained aluminum matrix containing two populations of particles (30 vol.% of 300 nm Al2O3 incoherent dispersoids and 0.2–0.3 vol.% of 6–60 nm coherent Al3Sc precipitates), was studied. At ambient and elevated temperatures, both populations of particles contribute to strengthening. At 300 C, creep threshold stresses are considerably higher than for control materials with a single population of either Al2O3 dispersoids or Al3Sc precipitates. This synergistic effect is modeled by considering dislocations pinned at the departure side of incoherent Al2O3 dispersoids (detachment model) and simultaneously subjected to elastic interactions from neighboring coherent Al3Sc precipitates. 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
منابع مشابه
Mechanical Properties of a Heat-Treatable Al-Sc Alloy Reinforced with Al2O3 Dispersoids
The mechanical behavior of precipitation-strengthened Al-0.18 wt.% Sc alloys containing 30 vol.% Al2O3 dispersoids is studied at 25, 300 and 350°C. The effect of Al3Sc precipitate size is studied by varying aging treatments. Microhardness measurements show that both populations of particles (nanometer-sized Al3Sc precipitates and submicron-sized Al2O3 dispersoids) contribute to strength at ambi...
متن کاملMechanical Properties and Microstructure of Al – Sc with Rare - Earth Element or Al 2 O 3 Additions
Mechanical Properties and Microstructure of Al–Sc with Rare-Earth Element or Al2O3 Additions Richard Albert Karnesky, Jr. Aluminum alloys strengthened with coherent (L12), nanosize Al3Sc precipitates are structural materials that have outstanding strength at ambient and elevated temperatures. They are creep resistant at 300 ◦C and exhibit a threshold stress, below which creep is not measurable....
متن کاملEffect of Mg addition on the creep and yield behavior of an Al–Sc alloy
The relationships between microstructure and strength were studied at room temperature and 300 °C in an Al–2 wt% Mg–0.2 wt% Sc alloy, containing Mg in solid-solution and Al3Sc (L12 structure) as nanosize precipitates. At room temperature, the yield strength is controlled by the superposition of solid-solution and precipitation strengthening. At 300 °C and at large applied stresses, the creep st...
متن کاملMg segregation at coherent and semi-coherent Al/Al3Sc interfaces
Aluminum alloys containing Sc are promising materials for high-temperature structural applications due to the high strengthening effect of the Al3Sc (L12 structure) precipitates [1]. Further improvements in strength and nanostructural stability of Al-Sc based alloys are achieved by adding alloying elements, such as Mg, as solid-solution strengtheners. It is important to understand the effects o...
متن کاملTHERMAL ANALYSIS AND KINETICS OF THE PRECIPITATION IN WROUGHT Al-Mg, Al-Mg-ScAND Al-Mg-Sc-Me (Me=Zr, Ti) ALLOYS
Precipitation behaviour of wrought Al-6Mg alloys with ternary scandium and quaternary zirconium and titanium has been studied. Hardness measurements and resistivity studies are employed to assess the precipitation behaviour of scandium doped Al-6Mg alloy without or with quaternary additions of zirconium and titanium. Further, the kinetics of precipitations are studied by differential scanning c...
متن کامل