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采用半固态混合-机械搅拌-超声施振的方法制备了体积分数为10%的SiCp/7085复合材料,通过金相显微镜、扫描电镜和X射线衍射对颗粒分布与界面进行研究,重点研究超声外场对复合材料颗粒团聚与界面结合的作用机理.实验结果表明:单纯机械搅拌对400目颗粒的团聚与界面结合的作用效果有限;超声外场下,空化作用产生的微射流与瞬时高温高压能够有效破除颗粒团聚体的包裹层,打散颗粒;超声破除颗粒表面氧化膜,除去气体层,使熔体中的镁元素与颗粒直接接触并反应是改善熔体与颗粒润湿性的重要因素;最终在界面处生成MgAl_2O_4强化相,从而获得更优的界面结合.
SiCp / 7085 composites with volume fraction of 10% were prepared by semi-solid-state mixing-mechanical stirring-ultrasonic vibration. The particle distribution and interface were studied by metallographic microscope, scanning electron microscopy and X-ray diffraction. On the mechanism of agglomeration and interfacial bonding between composite particles.Experimental results show that the effect of pure mechanical agitation on agglomeration and interfacial bonding of 400-mesh particles is limited. Microfluidization and transient high temperature and pressure generated by cavitation can be effective under ultrasonic field Breaking the parcels of the particle aggregates and breaking up the particles; ultrasonically breaking the oxide film on the surface of the particles to remove the gas layer so that the magnesium element in the melt directly contacts and reacts with the particles, which is an important factor for improving the wettability of the melt and the particles; finally The MgAl 2 O 4 strengthening phase is generated at the interface to obtain better interface bonding.