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用添加细化剂的方法细化铝合金熔体结晶时的晶粒,可减小铸态晶粒尺寸,这对于提高铸锭的抗裂纹能力,改善铝制品的机械性能,以及提高表面光亮度的均匀性都是很重要的。本文介绍了实现晶粒细化的方法,着重介绍在工业生产中采用的控制成核和晶核长大两方面的实用方法。通常使用的促进成核的铝基中间合金在成分和性能上都不一样。本文除了讨论中间合金细化晶粒的能力之外,还介绍了预测它们的细化效果的方法,以及关于规定特性方面的要求。除非凝固时的条件对于成核粒子(在溶解时它们被释放出来而进入熔体)的生长是适当的,否则这些中间合金在使用中是不能完全发挥其效力的。因此,本文对控制晶核生长条件起支配作用的一些参数作了介绍。对晶粒细化的发展趋势作了预测,主要在于减少中间合金质量的不稳定性,提高成核剂性能的方法以及对于含钛量高的回收铝适用的中间合金。同时认为,对中间合金细化机理的理解将有助于制造出细化效果比现有中间合金更好的晶粒细化剂。
Using the method of adding refiner to refine the crystal grains of the aluminum alloy during melt crystallization can reduce the as-cast grain size, which is of great value in improving the crack resistance of the ingot, improving the mechanical properties of the aluminum product and improving the surface brightness Uniformity is very important. This paper presents a method of grain refinement, highlighting practical methods for controlling nucleation and nucleation and growth in industrial production. Commonly used to promote nucleation of the aluminum-based master alloy in composition and performance are different. In addition to discussing the ability of intermediate alloys to refine grains, this article also presents methods for predicting their refinement, as well as the requirements for defining characteristics. Unless the conditions at the time of solidification are appropriate for the growth of the nucleating particles which enter the melt as they are released, they can not fully exert their effect in service. Therefore, some parameters that dominate the control of crystal growth conditions are introduced in this paper. The trend of grain refinement was predicted, mainly in terms of reducing the instability of the quality of the master alloy, improving the performance of the nucleating agent and the application of the master alloy for the recovery of aluminum with high content of titanium. At the same time, it is believed that the understanding of the refining mechanism of the intermediate alloy will help to create a better grain refiner with a better refining effect than the existing master alloys.