Effect of Zr content on microstructure and tensile properties of cast and T6 heat-treated A356-0.3Yb alloy

Abstract In this paper,the influence of different Zr addition amounts on the microstructure and tensile properties A356 alloy modified by 0.3wt%Yb in cast state T6 heat-treated were systematically investigated. The results show that adding basis can further refine α-Al eutectic Si branches. When content is 0.25wt%, has smallest grain size 133µm, aspect ratio 1.6. However, excessive will weaken effect Yb make start coarsening. forms (Al,Si)3(Zr,Ti) phase with Ti alloy, provides heterogeneous nucleation base, increases number grains, refines matrix. After heat treatment, spheroidized decreases to 1.3. strength elongation under condition are 187.4MPa 5.6% respectively, which 8.7% 30% higher than those without Zr. after treatment 296.3MPa 9.2% 6.3% 18%