The effects of Sc content on the mechanical properties of Al-Sc alloys were investigated.The results show that the strengths of all the tested alloys with 0.1 wt.%,0.3 wt.%,and 0.4 wt.% Sc additions increase initially with an increase in annealing time,due to the increase in volume fraction and size and the decrease in particle interspacing of Al3Sc particles.After reaching peak values,the strengths of all the tested alloys start to decrease with increasing annealing time due to the coarsening and increase in particle interspacing of Al3Sc particles.It has also been shown that the alloy with 0.3 wt.% Sc has a higher strength and a lower elongation than the alloys with 0.1 wt.% and 0.4 wt.% Sc.The increase in strength and the decrease in elongation of the alloy with 0.3 wt.% Sc are due to the smaller particle interspacing of Al3Sc particles,resulting in a strong inhibition of dislocation movement during deformation. The effects of Sc content on the mechanical properties of Al-Sc alloys were investigated.The results show that the strengths of all the tested alloys with 0.1 wt.%, 0.3 wt.%, And 0.4 wt.% Sc additions increase initial with an increase in annealing time, due to the increase in volume fraction and size and the decrease in particle interspacing of Al3Sc particles. After reaching peak values, the strengths of all the tested alloys start to decrease with increasing annealing time due to the coarsening and increase in It has also been shown that the alloy with 0.3 wt.% Sc has a higher strength and a lower elongation than the alloys with 0.1 wt.% and 0.4 wt.% Sc. increase in strength and the decrease in elongation of the alloy with 0.3 wt.% Sc are due to the smaller particle interspacing of Al3Sc particles, resulting in a strong inhibition of dislocation movement during deformation.