Effect of green preform composition, temperature and duration conditions on microstructure and performance of Al-5Ti-0.2C master alloy

Al-5Ti-0.2C master alloy was prepared via a simple combustion synthesis approach. By means of different smelting parameters, changes in its microstructure and refining performance were studied. Under short holding conditions (5 – 10 min) increase of Al content in the preform from 10 % to 40 % results in more numerous carbon-rich particles in the master alloy and better refinement performance. Nevertheless, preparation of refiner with satisfactory refining ability requires longer holding conditions (30 min). With prolonged holding time after the combustion, alloys possess similar microstructure and refining efficacy regardless of the chemical composition of the preform. Decrease of smelting temperature from 1 250 °C to 950 °C results in noticeable deterioration of the master alloy refining performance. The reasons, which impede successful utilization of primary benefits provided by combustion reaction, are discussed.