Microstructures and properties of AlZnMgCu alloys refined by nano Al₃Ti-TiB₂-AlN-TiN/Al inoculant ribbons

Nano Al₃Ti-TiB₂-AlN-TiN/Al inoculant ribbons containing a large number of evenly distributed nanoparticles, such as Al₃Ti (sized about 300 nm), TiB₂ (sized about 100 nm), AlN (sized about 150 nm), and TiN (sized about 200 nm), were prepared by vacuum rapid quenching furnace to refine AlZnMgCu alloys. The nano Al₃Ti-TiB₂-AlN-TiN/Al inoculant ribbons showed an excellent inoculant effect, which modified the dendrite crystals to equiaxed crystals and refined the grains from 122 ± 4 µm to 36 ± 5 µm by the addition of 0.3 wt% nano Al₃Ti-TiB₂-AlN-TiN/Al inoculant ribbons. In addition to nano Al₃Ti and TiB₂ particles, nano AlN and TiN particles also have a certain orientation relationship with α-Al, which suggests that these particles possess nucleation potency to α-Al. After inoculation with 0.3% nano Al₃Ti-TiB₂-AlN-TiN/Al inoculant ribbons, the ultimate tensile strength, yield strength, and average microhardness of the AlZnMgCu alloys increased from 246 MPa, 79 MPa, and 112 HV to 319 MPa, 100 MPa, and 136 HV, or by 29.7%, 26.6% and 21.4%, respectively.