Improvement of yttrium on the hot tearing susceptibility of 6TiB2/Al-5Cu composite

To improve the severe hot tearing susceptibility of TiB2 reinforced Al-5Cu matrix composites, the present research investigated the influence of Y on the hot tearing susceptibility of 6TiB(2)/Al-5Cu composite. For the composite added with Y, the solidification temperature range was shortened, which was caused by the novel tau(1)-Al8Cu4Y phase. The grain size of 6TiB(2)/Al-5Cu composite was 39.8 mu m. The addition of Y promoted the grain refinement, and the grain sizes were 36.33, 33.42 and 26.77 mu m for 6TiB2/Al-5Cu with 0.2 wt.%, 0.5 wt.% and 1 wt.% Y, respectively. The decrease of solidification temperature range and grain size was beneficial to the hot tearing susceptibility improvement. Furthermore, the hot tearing initiation force increased from 44 to 288 N, when 1 wt.% Y was added in 6TiB2/Al-5Cu. For the above significant influence, the hot tearing susceptibility values were reduced by 12.2 wt.%, 57.7 wt.% and 66.8 wt.% for 6TiB(2)/Al-5Cu with 0.2 wt.%, 0.5 wt.% and 1 wt.% Y, accordingly.