钛合金齿轮LPES法表面强化的电场与流场

针对TC4钛合金齿轮复杂曲面液相等离子体电解渗透(LPES)表面强化放电困难的问题,基于仿真分析和实验验证的方法,建立了齿轮表面强化系统仿真模型,进行了强化系统电场和流场仿真,确定了齿轮复杂表面放电机理,研究了电极系统参数和入口流速对强化层形成的影响。结果表明:齿轮复杂表面放电困难的根本原因在于电场的分布不均。采用啮合形阳极时的电场和强化层均匀性较好。电极距离过小容易造成强化系统的短路,过大时会降低强化层的均匀性和厚度。合理的系统电解液流速对放电的稳定性和强化层的形成均具有重要的意义。相较于未处理时的基体,强化后的齿轮表面耐磨性有了明显提升。

Electric field and flow field of LPES surface strengthening of titanium alloy gear

For the problem of forming stable arc discharge on the complex surface of the TC4 titanium alloy gears treated by liquid plasma electrolytic saturation (LPES), a simulation model of the gear surface strengthening system was established, the electric field and flow field were simulated based on simulation analysis and experimental verification methods. The discharge mechanism on the complex surface of the gear was determined. The effects of electrode system parameters and inlet velocity on the formation of the strengthening layer were studied. Results indicated that the fundamental reason for the difficulty of effective discharge on the gear surface was attributable to the uneven electric field. The uniformity of the electric field and the strengthening layer were better when the meshing anode was used. Too small electrode distance was likely to cause short circuit of strengthening system, and too large electrode distance could reduce uniformity and thickness of strengthening layer. Appropriate electrolyte flow rate is important for both the stability of the discharge and the thickness of the strengthening layer. Compared with the untreated substrate, the surface wear resistance of the strengthened titanium alloy gear has been significantly improved.