铜/钛双金属液固复合界面元素扩散行为研究

Diffusion Behavior of Elements at Cu/Ti Bimetallic Liquid-Solid Composite Interface

摘要:

采用液固复合工艺制备铜钛复合材料，借助OM、SEM、EPMA等测试方法研究了复合界面Cu、Ti元素的扩散行为。结果表明：在铜/钛复合的过程中，晶界是扩散的主要通道。除了部分Cu₄Ti相在Cu基体上形成外，扩散溶解层其余的化合物相都在Ti基体上生成。铜钛复合界面上形成的化合物相有Cu₄Ti、Cu₃Ti₂、CuTi、CuTi₂。其中，Cu₃Ti₂相以“锯齿状”方式生长，CuTi相以“竹笋状”方式生长，CuTi₂相以“平面状”方式生长。扩散溶解层的硬度值明显高于2种纯组元的硬度值。经Miedema模型计算，界面相析出先后顺序为CuTi、Cu₃Ti₂、CuTi₂、Cu₄Ti。铜与钛的液固复合是铜在钛基体中的扩散和钛在铜液中的溶解共同作用的结果。

Abstract:

The Cu-Ti bimetallic composites were prepared by liquid-solid composite process, and the diffusion behavior of Cu and Ti elements at the composite interface was investigated by OM, SEM, EPMA and other testing methods. The results show that the grain boundaries are the main channels for diffusion in the process of Cu/Ti composite. Except for part of the Cu₄Ti phase formed on the Cu matrix, the rest of the compound phases of the diffusively-dissolved layer are generated on the Ti matrix. The compounds generated at the Cu-Ti composite interface are Cu₄Ti, Cu₃Ti₂, CuTi and CuTi₂, where the Cu₃Ti₂ phase grows in a “jagged” manner, the CuTi phase grows in a “bamboo shoot” manner, and the CuTi₂ phase grows in a “planar” manner. The hardness values of the diffusion-dissolved layer are significantly higher than those of the two pure components. As verified by the Miedema model, the sequence of interfacial phase precipitation is CuTi, Cu₃Ti₂, CuTi₂ and Cu₄Ti. The bonding of Cu and Ti is a combined action of Cu diffusion in Ti matrix and Ti dissolution in the Cu solution.