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采用镶嵌式扩散偶技术制备Al/Ti扩散偶,在Al熔点以上Ti熔点以下进行扩散热处理,研究Al/Ti液/固界面扩散溶解层的组织结构演变、形成机制及生长规律。实验结果表明,热处理后的扩散溶解层为TiAl3颗粒和含少量Ti的铝基固溶体的混合组织;TiAl3相是热处理过程中最先出现也是唯一出现的新生相;扩散溶解层的生长机制和生长方向随热处理时间的延长发生了改变,在热处理开始后一段时间,扩散溶解层的生长受化学反应速度控制,与保温时间呈线性关系,之后,转变为受扩散控制,与保温时间呈抛物线关系,扩散溶解层的生长方向也由Ti基侧转变为Al基侧;扩散溶解层的厚度与热处理温度呈指数关系。
The Al / Ti diffusion couple was prepared by the mosaic diffusion technique, and the diffusion heat treatment was performed below the melting point of Ti above the melting point of Al to study the microstructure evolution, formation mechanism and growth law of diffusion / dissolution layer of Al / Ti liquid / solid interface. The experimental results show that the diffusion-dissolved layer after heat treatment is the mixed microstructure of TiAl3 particles and the aluminum-based solid solution containing a small amount of Ti. The TiAl3 phase is the first and only emerging phase during the heat treatment. The growth mechanism and growth direction of the diffusion- With the increase of heat treatment time, the growth of the diffusion-dissolved layer was controlled by the chemical reaction rate and a linear relationship with the holding time after a certain period of time after the heat treatment began. After that, the diffusion-controlled solution was changed into diffusion-controlled, The growth direction of the dissolved layer also changes from the Ti-based side to the Al-based side. The thickness of the diffusion-dissolved layer is exponential with the heat treatment temperature.