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通过原位反应制备Mg_2Si增强Al基复合材料,研究熔体过热处理温度和保温时间对Mg_2Si/Al-Si复合材料组织与性能的影响,确定最佳的工艺参数。结果表明:在本实验条件下,熔体过热处理的最佳工艺为820℃保温30 min,初生Mg_2Si接近于球状,平均晶粒尺寸为17μm,共晶Si由粗大的枝晶状变成细小的颗粒状,共晶Mg_2Si由汉字状变成短棒状,分布较均匀。未进行保温处理时,初生Mg_2Si的晶粒尺寸随着过热温度的提高而减小;过热温度低于870℃时,初生Mg_2Si的晶粒尺寸随保温时间的延长而减小;过热温度高于870℃时,初生Mg_2Si晶粒尺寸随保温时间的延长而急剧增大。
The effects of melt overheating temperature and holding time on the microstructure and properties of Mg_2Si / Al-Si composites were investigated by in-situ reaction to prepare Mg_2Si reinforced Al matrix composites. The optimum technological parameters were determined. The results show that under the experimental conditions, the optimum process of melt overheating treatment is 820 ℃ for 30 min, the primary Mg 2 Si is nearly spherical, the average grain size is 17 μm, the eutectic Si is changed from coarse dendrite to fine Granular, eutectic Mg_2Si from Chinese characters into short rod-shaped, more evenly distributed. Without heat preservation, the grain size of primary Mg_2Si decreases with the increase of overheating temperature; when the temperature is lower than 870 ℃, the grain size of primary Mg_2Si decreases with the increase of holding time; the overheating temperature is higher than 870 ℃ ℃, the size of primary Mg_2Si grains increases sharply with the extension of holding time.