LPBF制备Al-Ce-Sc-Zr合金的短时时效组织演化与力学性能研究OA

Based on thermodynamic calculations,a novel Sc-and Zr-microalloyed Al-Ce alloy was designed,and Al-10 wt.％Ce-0.3 wt.％Sc-0.25 wt.％Zr was selected as the target composition.The alloy was fabricated using laser powder bed fusion(LPBF).Combined with the isothermal age-hardening curve at 300℃,the microstructures and room-temperature tensile properties of the as-built alloy and the sample aged at 300℃ for 1 h were analysed.After aging at 300℃ for 1 h,a hierarchical microstructure consisting of microscale AlnCe3 eutectic phases,nanoscale L12-Al3(Sc,Zr)precipitates,and nanoscale stacking faults is formed in the alloy.Compared with the as-built state,the yield strength increases from(334.2±5.3)MPa to(391.3±6.1)MPa,and the ultimate tensile strength increases from(463.8±1.6)MPa to(552.9±6.5)MPa after aging for 1 h,without causing an obvious loss of ductility.The strength enhancement is attributed mainly to the effective impediment of dislocation motion by L12-Al3(Sc,Zr)precipitates and stacking fault structures,whereas the retention of ductility is associated with local stress relaxation and improved deformation compatibility induced by microstructural recovery during aging.