Study On Grain Refining Property And Preparation Of Al-5Ti-1B Wires

Fine and uniform microstructure is a simple and effective way to achieve high-quality aluminum alloy. In many ways of grain refinement of aluminum and aluminum alloys, controlling the solidification process is its core to achieve the refinement purpose. One of the most typical and most commonly used in industrial production method is added to the aluminum melt before pouring aluminum refiner. Currently, the most commonly used aluminum and aluminum refiner Al-5Ti-1B refiner.This paper used two methods of the fluoride salts method and titanium method prepared Al-5Ti-1B master alloy, its second phase were effective Al3Ti and TiB2. The tests proved that:under the same conditions, that was good absorption rate using K2T1F6and KBF4than Ti powder and KBF4in the preparation of master alloys, The absorption rate of Ti and B were95%and99%, and the size of generated second phase Al3Ti was between5μm-20μm, and more uniform distribution,we also studied the different cooling rate, magnetic field of the preparation of the alloy. The test showed that:the faster cooling rate conducive to the intermediate alloy of Al-5Ti-1B of the second phase distribution. In the case of slow cooling rate, the second phase of the alloy appeared a certain degree of agglomeration; As the cooling rate increased, the second phase TiAl3size became smaller, maximum size could be reduced from30μm to10μm, and regular shape and more uniform distribution. The effect of the magnetic field strength did not affect the second phase shape in the alloy, but would change the size of the second phase, so that the second phase was smaller size.Finally, this article carried out hot compression test. The best thermal processing parameters was simulated through the establishment of the constitutive equations and processing maps. Hot extrusion test was carried out under this parameter, and extruded Φ12mm wires. After hot extrusion processed the alloy second phase occurs crushing, the shape the second phase changed fine and smaller in the alloy, the second phase would linear distribution along the direction of the hot extrusion, we conducted the refinement test using refiner by hot extrusion processing of Al-5Ti-1B wire to pure aluminum, studied the impact of the added amount of the refinement and different refining contact time on the thinning effect. The test showed that:Al-5Ti-1B wire had good refining effect to industrial aluminum. After Al-5Ti-1B wire refiner refined pure aluminum coarse grains apparently disappeared and changed into the fine equiaxed grain. Moreover, under the same conditions, the refiner added0.8%(by the mass fraction), the refining contact time20min was best.