过滤铸造对高硅铝合金中初晶硅尺寸的控制

Control of Primary Silicon Grain Size in Hypereutectic Al-Si Alloys by Filtering Casting Method

摘要:

初晶硅颗粒的细化是过共晶高硅铝合金制备过程中的一个主要问题。本研究提出了一种通过过滤的方式来获得含有细化初晶硅颗粒的高硅铝合金的方法。在过滤铸造的过程中，过共晶硅铝合金熔体保持在Al-Si二元相图共晶线偏上一点的温度。大颗粒初晶硅被筛网阻拦下来，细小的初晶硅颗粒连同共晶熔体穿过筛网进入下部坩埚冷却结晶。在本研究中通过以上方法所制备的高硅铝合金中硅的质量分数约为27%，初晶硅颗粒的平均直径在45 μm以下，圆度为1.43，布氏硬度为70 HB。通过该方法有望制备出初晶硅颗粒球形度更高、硅含量更高的高硅铝合金产品。

Abstract:

The main technical problem in the preparation of hypereutectic Al-high Si alloy is the refinement of the primary Si particles. In this paper, a new method for the preparation of Al-high Si alloy with refined primary Si particles by filtration treatment is proposed. During this process, the melt of hypereutectic Al-Si alloy underwent the filtration treatment at the temperature of little above the eutectic line in the Al-Si binary phase diagram. After that, the large-sized primary Si particles were retained by the filter screen, while the small-size primary Si particles together with the eutectic melt went through the screen and cooled down, forming into the hypereutectic Al-high Si alloy products. The Si content in the Al-high Si alloy prepared in this study was about 27 wt.%, the average diameter of the primary Si particles reached less than 45 μm, the roundness of the primary silicon particles was 1.43, and the brinell hardness of the alloy was about 70 HB. By this method, it is expected to obtain the Al-high Si alloy with higher degree of sphericity of the primary Si particles and higher Si content.