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非连续增强金属基复合材料是金属基复合材料中最有工业应用前景的新材料,其中界面微结构是决定复合材料性能的关键。着重研究了SiCp原始态和氧化处理态以及Al_2O_3p等增强体在挤压铸造和搅拌铸造复合条件下,与不同的铝基和锌基合金复合后的界面微观结构特征。研究结果表明,氧化后的SiCp与基体界面的SiO_2层在电子束辐照下,将由晶态转变为非晶态,从而圆满解释了以往存在的X射线分析结果与电子衍射分析结果的矛盾。研究氧化后的SiCp与铝基体复合后的界面行为发现,对于纯铝基体,SiO_2层的形成有利于界面强度的增大,并发现在SiO_2层中存在铝元素的浓度梯度,较好地解释了由于扩散结合使界面得到加强的结果,而对于Ly12基体,由于表面的SiO_2层与基体中的镁反应生成MgAl_2O_4,使基体中含镁的强化相明显减少,削弱了时效强化的效果,使复合材料强度反而降低。 对搅拌铸造法制备的Al-Mg基复合材料,分别观察了不同增强体的界面反应产物和存在的界面取向关系,并探讨了其反应机制。最后,对SiCw增强的锌基复合材料的固态反应动力学和微观结构进行了研究,观察了晶须与基体之间的结合状态。
Non-continuous reinforced metal matrix composites are the most promising materials for industrial applications in metal matrix composites. The interfacial microstructure is the key factor that determines the properties of composites. The interfacial microstructural features of SiCp original and oxidized state and Al_2O_3p reinforcements, which were compounded with different Al-based and Zinc-based alloys, were investigated emphatically under the conditions of squeeze casting and stirring casting. The results show that the SiO 2 layer at the interface between the oxidized SiCp and the matrix changes from crystalline to amorphous under electron beam irradiation, which satisfactorily explains the contradiction between the X-ray analysis and the electron diffraction analysis. It is found that the formation of SiO_2 layer is conducive to the increase of the interfacial strength for the pure aluminum matrix and the presence of the concentration gradient of aluminum element in the SiO_2 layer is better explained by the results of the interfacial behavior of the oxidized SiCp and the Al matrix. However, for the Ly12 matrix, MgAl_2O_4 reacts with magnesium in the matrix due to the reaction of the SiO_2 layer on the surface, which leads to a significant decrease of the strengthening phase of magnesium in the matrix, which weakens the effect of aging strengthening and makes the strength of the composite But lower. The Al-Mg matrix composites prepared by the stirring casting method were respectively observed the interfacial reaction products of the different reinforcements and the existing interfacial orientation relationship, and the reaction mechanism was discussed. Finally, the solid state reaction kinetics and microstructure of SiCw reinforced zinc matrix composites were studied, and the bonding between whiskers and matrix was observed.