超声外场下SiC_p/7085复合材料界面结合机理

Interface bonding mechanism of SiC_p/7085 composite in ultrasound field

采用半固态混合—机械搅拌—超声搅拌工艺制备体积分数为10%的SiC_p/7085复合材料,通过扫描电镜(SEM)和能谱仪(EDS)分析制备过程中2种粒度SiC颗粒的界面结合、界面相及成分的演变规律,研究超声外场对复合材料界面结合的影响机理。研究结果表明:半固态混合—机械搅拌工艺基本实现了大粒度SiC颗粒与基体的界面结合,但在界面处生成了大量Al_4C_3,而对于小粒度颗粒,机械搅拌的作用效果不明显;超声外场作用下的空化效应产生高温高压,有效改善小颗粒与熔体的润湿性,并使得Mg元素在界面处富集,生成MgO和MgAl_2O_4等界面强化相,获得更优的结合界面。

SiCp/7085 composites with 10% （volume fraction） particle were fabricated by semi-solid mixture, mechanical stirring and ultrasonic radiation process. The evolution of interfacial combinative state, interface phase and composition between the particles of two sizes and melt during the fabrication process was investigated by SEM and EDS to research the mechanism of the ultrasonic radiation transformation interface. The results show that the semi-solid mixture and mechanical stirring process accomplish the wetting between the larger particles and melt in the main, while generate A14C3 at the interface, but there is not remarkable improvement of wettability between the small particles and melt. As a result of ultrasonic radiation, Mg is reriched at the interface, which gives rise to the formation of interface strengthening phase MgO and MgA1204, the interface bonding is stronger than that of semi-solid mixture and mechanical agitation.