Effect of Sc and Zr addition on mechanical properties of cellular aluminum foam

Utilizing Ca and TiH2 as the thickening agent and blowing agent， respectively， Al-0.16Sc， Al-0.21Sc， and Al-0.16Sc-0.17Zr cellular foams with porosity of （72±0.5）% were successfully fabricated by the melt-foaming method. The microstructure and compressive strength of the foams with isochronal aging treatment were investigated. The results show that during isochronal aging between 200 ℃ and 600 ℃， Al-0.16Sc and Al-0.21Sc foams achieve their peak yield strengths （about 21.4 MPa and 26.8 MPa， respectively） at 325 ℃ due to the precipitation strengthening of Al3Sc/Al3（Sc1-xTix）. Unlike the Al-Sc foam， the yield strength of the Al-0.16Sc-0.17Zr alloy foam reaches 23.7 MPa at 325 ℃ and 24.7 MPa at 400 ℃， representing an increase of 100.8% and 109% than those of the cast alloy， respectively. Zr addition not only significantly enhances the strength of the Al-Sc foams， but also effectively affects the coarsening of the Al3Sc/Al3（Sc1-xTix） precipitate.