Scandium-enriched nanoprecipitates in aluminum providing enhanced coarsening and creep resistance

Abstract

The development of high temperature aluminum alloys able to operate up to 400 ºC is crucial to replace steel and titanium and decrease the mass of vehicles in the automotive and aerospace industries. This review relates the past two decades of aluminum alloy engineering done at Northwestern University focusing on developing coherent L12 Al3M nanoprecipitates strengthened aluminum alloys that are coarsening and shear-resistant at high temperature. Starting with the Al-Sc binary system, each new generation of alloys has become more complex to improve the alloy’s mechanical properties and coarsening resistance at high temperatures. The effects of rare-earth (Er, Y, Sm, Gd, Tb, Dy, Ho, Tm, Yb, Lu), transition metals (Zr, Ti, V, Nb, Ta), inoculants (Si, In, Sb, Sr, Ge, Zn) and solid solution (Mg, Li) elements onto the L12 Al3M precipitates is reviewed. The most recent alloys have optimized strength, coarsening resistance and lower prices, opening the doors to wider application uses.