Ti基复合材料制备及热处理条件下扩散连接的理论及实验研究(英文)

Experimental and Theoretical Study of Diffusion Bonding in Fabricating and Annealing Ti Matrix Composite

通过Ti6Al4V/TA1扩散偶的制备及其热处理试验,运用OPM,SEM以及EDS技术对扩散连接区域的组织、形貌、成分进行分析。结果表明:扩散连接界面充分结合,合金元素Al和V从Ti6Al4V侧向TA1侧扩散,而Ti原子向Ti6Al4V侧扩散,其成分过渡区满足抛物线规律;同时,根据柯勒方程,借助米德玛生成热模型,从热力学上推导三元体系的计算公式,得出热力学相互作用因子,并根据求得溶质元素的互扩散系数,通过唯象公式的数值解法,得出扩散元素在连接界面处的理论浓度分布图;实验值与理论模拟结果吻合得很好,因此,能够很好的预测扩散连接界面相关元素的浓度分布。

Ti6A14V/TA1 diffusion couples were fabricated and then heat-treated in vacuum under different conditions. The microcosmic metallographic structure, morphologies and the composition distribution in diffusion bonding zone were studied by using of OPM, SEM and EDS methods. The results show that diffusion couples are bonded well, and the alloying elements A1 and V diffuse from Ti6A14V to TA1, and Ti atoms diffuse in the opposite direction. The transition zone of the alloying elements follows a role of parabolic rate. At the same time, based on Koher＇s ternary solution model and Miedema＇s model for calculating the thermodynamical interaction coefficients, as well as according to the inter-diffusion coefficients of the alloying elements and the numerical solution of the phenomenological equation, the theoretical diffusion profiles of alloying elements and Ti are obtained, which are well fitted to the experimental data. So it can predict the distribution of the diffusion atoms at the diffusion bonding interface.