Hypoeutectic aluminum-silicon alloy refinement and modification method

Abstract

The invention provides a hypoeutectic aluminum-silicon alloy refinement and modification method. The method includes the steps that aluminum powder, titanium powder, carbon powder and Ce2O3 powder are mixed and then pressed to form a mixed powder block; metal aluminum is heated till being completely molten, and aluminum melt is obtained; pouring is conducted after the mixed powder block is pressed in the aluminum melt to be subjected to thermal expansion reaction, and an Al-Ti-C-Ce refiner is obtained; and pouring is conducted after hypoeutectic aluminum-silicon alloy melt and the Al-Ti-C-Ce refiner with the mass accounting for 0.5%-2% of the hypoeutectic aluminum-silicon alloy melt are mixed. According to the method, the powdery raw materials are processed into the compact block, then, the mixed powder block is added in the aluminum melt for reaction, sufficient reaction of elements is ensured, the reaction time is shortened, and more energy is saved; and the titanium powder is used as a titanium source, and compared with a traditional method introducing K2TiF6 as the titanium source, no fluorination gas can be generated in the preparation process, no environment pollution can be caused and the method is more environment-friendly.

Description

technical field [0001] The invention relates to the technical field of alloy refinement, in particular to a method for refinement and modification of a hypoeutectic aluminum-silicon alloy. Background technique [0002] Hypoeutectic Al-Si alloys are widely used in aerospace, automobiles, motorcycles and other vehicles because of their advantages such as low density and excellent casting properties. The hypoeutectic Al-Si alloy mainly contains primary α-Al phase and eutectic Si, in which the α-Al phase is in the form of coarse dendrites, and the eutectic Si phase is precipitated in the form of coarse needles or laths. The splitting effect of the matrix seriously affects the mechanical properties of the alloy, resulting in the low mechanical properties of the Al-Si alloy, especially the low elongation and poor toughness. [0003] Adding a grain refiner to the alloy can not only refine the as-cast grains and dendrite structure, but also reduce porosity, reduce hot cracking tend...

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Problems solved by technology

However, due to the poor wettability of C in Al, the preparation is very difficult. The Al-Ti-C grain refiner is prepared by strong stirring or high-temperature reaction, and the preparation cost is high, which limits the Al-Ti-C grain refinement. Application of oxidizing agent in aluminum alloy refinement

[0004] Wang Liandeng of Fuzhou University and others made the rare earth oxide Ce 2 o 3 Al-Ti-C-Ce refining agent was prepared to refine metal aluminum by replacing single rare earth element Ce and adding it to Al-Ti-C alloy, but K was used in the preparation process 2 TiF 6 , a large amount of fluoride gas is produced in the preparation process, which causes great pollution to the environment, and the preheating and holding time of raw materials in the preparation process is long, and the energy consumption is high

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