Design and Processing Conditions of Hypoeutectic Al-Cu-Sc Alloys for Maximum Benefit of Scandium

摘要

Addition of Sc to Al-Cu is reported to be responsible for a high precipitation hardening upon heat treatment and serves as a good grain refiner. However, Scandium is presently very expensive, therefore, getting maximum benefit from a minimum addition would be economically of value. This work studies microstructures and mechanical properties of hypoeutectic Al-4.5 wt%Cu-xSc (x = 0.1, 0.2 or 0.4 wt%) of various thermal histories. Samples are generated under a wide range of cooling rates and undercooling by two different methods, including Differential Scanning Calorimetry and Impulse Atomization. In as-solidified as well as in heat treated conditions, the samples are investigated by means of Electron Microscopy, diffraction analysis and microhardness measurements. The results of this work identify those processing conditions that make optimum use of the Sc in enhancing the mechanical properties of the Al-Cu alloy.