This research presents the effect of high Ti (3.0wt%) and B (1.4wt%) content on the hot tearing, microstructure and mechanical properties of high strength A201(Al-Cu-Ag-Mg) aluminum alloys, the analyzed methods including hot tearing test, optical microscope (OM), electron probe micro analyzer (EPMA), electrical conductivity meter (% IACS), tensile test...ellipses. The results showed the average grain size of as-cast state alloys decreased from 105μm to 45μm due to high Ti (3.0wt%) and B (1.4wt%) added. Besides, the intermetallic compounds such as TiB2, Al3Ti formed in the Al-Matrix. Compared to unmodified alloys, the tensile strength and hardness of high Ti and B content alloys increased about 7.1% and 15% after T7 heat treatment, up to 418MPa and 83HRB. Showed the improvements of mechanical properties on high Ti and B content heat-treatable A201 alloys was slight, although the intermetallic compounds had dispersion strengthening effect. Castability was analyzed by hot tearing molds and the results showed the resistance of hot tearing improved significantly. The amount of unbroken test bar of modified alloys is three while the un-modified alloys is zero. The hot cracks morphology also indicated the resistance of hot tear improved with the addition of high Ti and B. Besides, compared to add Ti or B lonely, the alloys has the best castability while Ti and B were added together. That’s because the formation of the intermetallic compounds TiB2 which has low thermal expansion coefficient can improve the hot tearing resistance.
