Creep property and microstructural evolution of laser powder bed fused binary Al–10Ce alloy

Abstract

Aluminum–Cerium (Al–Ce) based alloys have shown promise as cost-efficient high temperature creep-resistant aluminum alloy. These alloys are also highly printable with laser powder bed fusion (LPBF) additive manufacturing. This study investigates the creep property of a near eutectic binary Al–10Ce (wt. %) alloy manufactured by LPBF and its microstructural evolution during creep. The as-built alloy exhibited columnar grain structure with a weak cube texture and its microstructure consisted of fine eutectic Al + Al11Ce3. Compressive creep tests with incremental stresses were performed perpendicular to the build direction at temperatures ranging from 275 to 400 °C. The stress exponent was approximately 1 in the low stress regime and 5–7 in the high stress regime, corresponding to diffusion and dislocation creep, respectively. The average activation energy was approximately 229 kJ/mol·K in the temperature between 275 and 375 °C. After creep deformation, the melt pool boundary faded and the eutectic Al11Ce3 intermetallics slightly coarsened. The grain structure remained relatively stable and the grain boundary became more pronounced. By comparing the minimum creep strain rate to other alloys, it was found that LPBF Al–10Ce is more creep resistant than similar cast binary Al–Ce counterpart, some ternary Al–Ce alloys and LPBF AlSi10Mg alloy. This benchmark results on the creep property of LPBF binary eutectic Al–Ce alloy provide insights to future development of creep-resistant Al–Ce alloys.