Effect of Al-5Ti-1B Grain Refiner on Microstructure and Mechanical Properties of 7075 Aluminum Alloy

The microstructure of Al-5Ti-1B grain refiner was analyzed by XRD and SEM. The effect of the Al-5Ti-1B grain refiner on the microstructure and mechanical properties of 7075 aluminum alloy were studied. Results show that when the addition amount of Al-5Ti-1B grain refiner is 0.1%, the microstructure of 7075 aluminum alloy is refined from coarse dendrite to equiaxed grains with an average diameter of 55.1μm. The tensile strength and elongation of 7075 aluminum alloy are improved by 11.32% and 36.04% compared with that of 7075 aluminum alloy without adding Al-5Ti-1B grain refiner. With increasing the addition amount of Al-5Ti-1B grain refiner from 0.1% to 0.5%, both the tensile strength and elongation are improved. When the addition amount of Al-5Ti-1B grain refiner increases to 0.5%, the microstructure of 7075 aluminum alloy is refined to uniform equiaxed grains with an average diameter of 32.5μm. The tensile strength and elongation are improved by 18.11% and 48.76%, respectively.