Grain refining performance of Al–Ti(C _0.7 , N _0.3 ) master alloy and its effect on mechanical properties for commercial pure aluminium

A new Al–4.2 wt.% Ti(C _0.7 , N _0.3 ) master alloy with a uniform microstructure was successfully prepared by casting method. Grain refining test indicates that Al–4.2 wt.% Ti(C _0.7 , N _0.3 ) master alloy exhibits an excellent grain refining performance on commercial pure aluminium and the average grain size of pure Al can be effectively refined to 130 µm from about 3000 µm after adding 0.1 wt.% Ti(C _0.7 , N _0.3 ) particles by Al–4.2 wt.% Ti(C _0.7 , N _0.3 ) master alloy. The tensile strength and elongation are increased by about 20.5% from 55 to 66.3 and 14.9% from 39 to 44.8 due to the grain refinement by adding Al–4.2 wt.% Ti(C _0.7 , N _0.3 ) master alloy. Compared with Al–5Ti–1B master alloy, Al–4.2 wt.% Ti(C _0.7 , N _0.3 ) master alloy has a slightly better ability in improving the mechanical properties of pure aluminium due to the better grain refining performance.