制备工艺对原位合成(Al_2O_3+Si)_p/Al复合材料显微组织影响及体系分析

以Al-SiO_2为反应体系,通过烧结反应原位合成了(Al_2O_3+Si)_p/Al复合材料。研究了第二相含量、烧结时间以及热锻压等工艺对(Al_2O_3+Si)_p/Al复合材料的第二相形貌、尺寸及分布的影响,探讨了原位合成(Al_2O_3+Si)_p/Al复合材料的生成机制。研究表明,Si相含量随着第二相含量的增多而增多且与Al和Al_2O_3相界限相对明显;随着烧结时间的延长,Si相面积相对减小,Al_2O_3相的数量相对增加;锻压后,Si相和Al_2O_3分布更加均匀且尺寸减小。复合材料在液相烧结的过程中,高温下的液相粘性流动以及在原位反应时发生的颗粒重排与固相的溶解和沉淀对材料的致密化产生了较大的作用,当烧结温度达到1000℃时,Al_2O_3颗粒数量、分布情况都得到明显地改善。

Effects of Preparation Process on Microstructure of in-situ (Al2O3 +Si)p/Al Composites and the Analysis of Reaction System

In-situ (Al2O3 +Si)p/Al composites were synthesized by reaction sintered method from AlSiO2 system.The effects of content of second phase,sintering time and forging on the reinforced particles in (Al2O3 + Si)p/Al composites were instigated.The phase sintering mechanism in-situ synthesized (Al2O3 +Si)p/Al composites was discussed and analyzed.The result shows that when the content of second phase increases,the content of Si phases increase significantly and the interfaces between them gets remarkable.The area of Si phase decreases and the number of Al2O3increases as the sintering time prolonged.The forging significantly improves the distribution of Al2O3and Si phase and the grains are also refined.In the sintering process,the densification depends on fluidity of liquid phase at high temperature,rearrangement and solutionprecipitation stage.When the sintering temperature increase to 1000℃,the number of particle distribution of Al2O3 are considerably improved.