Study on the grain refinement of A356 alloy by Al-3 wt-% VN master alloy

摘要

A novel Al-3 wt-% VN master alloy, mainly consisting of a-Al and VN phases, was successfully prepared by stir casting. The grain refinement performance of the master alloy on A356 alloy was then investigated. The results showed that the a-Al grain size of A356 alloy refined by Al-3 wt-% VN master alloy was 350 ± 95 pm while that of A356 alloy treated by traditional Al-5Ti-B master alloy was 570 ± 105 pm. Moreover, for A356 alloy with AI-3 wt-% VN addition, the good grain refining efficiency did not fade significantly within 30 min. The effectiveness of grain refinement might be attributed to VN particles, which acted as the heterogeneous nuclei of a-Al grains. Owing to the refinement strengthening, the yield strength, ultimate tensile strength and elongation of A356 alloy were improved.