柔性电极电火花强化钛合金表面性能

采用旋转的柔性铜电极与钛合金表面在高频脉冲电源的作用下进行电火花表面强化,使空气中的氧等元素在放电形成的高温高压条件下与钛合金表面发生反应。结果表明:该试验条件下可以使钛合金表面硬度相对基体提高237%～399%;强化层厚度达到21～157μm;通过能谱分析(Energy dispersive spectrometer,EDS)及X射线衍射(X-ray diffraction,XRD)分析表明,在钛合金表面生成了钛的氧化物等强化物质和钛与铜、锌等的合金;强化表面不存在明显的传统放电蚀除凹坑,但有明显机械刮磨涂覆痕迹,同时单脉冲放电能量被分散,使得表面粗糙度值的提高量较小且可控;在氢氟酸和硝酸混合溶液中,强化层具有较高的抗腐蚀能力,经过点面磨损测试表明,强化层表面耐磨性能相对于基体表面有显著提高。经强化,能够获得具有良好耐磨性、抗腐蚀性、表面良好的钛合金。

Surface Property of Titanium Alloys by Electrospark Surface Strengthening of Flexible Electrode

Electrospark surface strengthening of titanium alloys is done by flexible rotating copper electrode with high-frequency pulse power supply.Then the oxygen and other elements from the air could react with titanium under the condition of high temperature and pressure caused by discharge.Experimental results show that the surface hardness of titanium alloy is improved by 237%—399% with reference to the substrate,and the thickness of the strengthened layer reaches a range of 21～157 μm.Through energy dispersive spectrometer(EDS) and X-ray diffraction(XRD) analysis,it is shown that titanium oxides and other strengthening matter such as titanium and copper/zinc alloys are generated on the titanium surface.In addition,obvious mechanical scraping and coating traces exist on the strengthening surface,but there are no significant traditional discharge erosion concave pits.At the same time,single pulse discharge energy is dispersed,thus the surface roughness value increases a little and is controllable.Besides,the strengthened layer has an improved ability of anti-corrosion in the mixed solution of hydrofluoric acid and nitric acid,and the enhanced layer has a high corrosion resistance.Point and surface wear tests show that the surface abrasion performance of the strengthened layer is improved significantly relative to the substrate surface.Good abrasion resistance,good corrosion resistance,and good quality of titanium alloy surface are obtained after being hardened.