Ti−6Al−2Zr−1Mo−1V合金TiB_(2)/TiB渗硼层实验和模拟

Experiment and modeling of TiB_(2)/TiB boride layer of Ti−6Al−2Zr−1Mo−1V alloy

对Ti−6Al−2Zr−1Mo−1V合金在920~1120℃温度范围进行渗硼处理,研究渗硼条件对渗硼层的影响。结果表明,渗硼层由外部连续薄TiB_(2)层和里层厚TiB层组成,TiB相呈魏氏体状或针状形貌嵌入基体。在渗硼温度为1000~1080℃、渗硼时间超过8 h渗硼时可获得厚而致密的渗硼层。渗硼层厚度随渗硼温度和渗硼时间增加而增加。渗硼层生长动力学曲线呈抛物线特征。建立TiB_(2)和TiB层生长动力学的预测模型,其计算结果与实验数据达到较好吻合。确定TiB_(2)和TiB激活能分别为223.1和246.9 kJ/mol。

The influence of the boriding conditions on the boride layers was examined by boriding Ti−6Al−2Zr−1Mo−1V alloy in the temperature range of 920−1120℃.The experimental results show that the boride layers were composed of a continuous thin outer layer of TiB_(2) and a thick inner layer of TiB with whiskers or needle-like morphologies that extended into the substrate.Thick and compact boride layers were obtained when the boriding temperatures were 1000−1080℃,and the treatment time exceeded 8 h.The boride layer depth increased with the boriding temperature and time,and the growth kinetics of the boride layers was characterized by a parabolic curve.The growth kinetics of the boride layers,including both TiB_(2) and TiB layers,were predicted by establishing a diffusion model,which presented satisfactory consistency with the experimental data.As a result,the activation energies of boron in the TiB_(2) and TiB layers were estimated to be 223.1 and 246.9 kJ/mol,respectively.