TC4钛合金混粉电火花表面改性研究

Surface Modification of TC4 Titanium Alloy by Mixed Powered Electrical Discharge Machine in Different Tool Electrode

目的通过混粉电火花加工方法,分别使用紫铜和石墨作为工具电极,获得综合性能较好的TC4钛合金表面。方法利用手持式TR200粗糙度仪对工件表面的粗糙度进行测量,用扫描电子显微镜(SEM)、X射线衍射仪对工件组织形貌和物相结构进行分析,用FM800型显微硬度计对工件表面进行显微硬度测量。结果在相同电参数下,紫铜电极加工的工件较石墨电极加工的工件表面粗糙度要低,硬度也相对低。当I=4.5A、tON=30?s时,紫铜电极加工的工件表面平均粗糙度值Ra=2.223?m,表面硬度约为600HV;石墨电极加工的工件表面平均粗糙度值Ra=2.796?m,表面硬度约为700HV。当I=9 A、tON=30?s时,紫铜电极加工的工件表面平均粗糙度值Ra=2.748?m,表面硬度约为650HV;石墨电极加工的工件表面平均粗糙度值Ra=3.705?m,表面硬度约为750HV。结论在不同电极条件下混粉电火花加工后,TC4钛合金工件表面都达到了强化的效果。

The work aims to obtain high surface quality of TC4 titanium alloy by means of mixed powder electrical discharge machining method with red copper and graphite as tool electrodes. The roughness of the workpiece surface was measured by handheld TR200 roughness tester, surface morphology and phase structure were analyzed by using scanning electron microscope （SEM） and X-ray diffraction, and micro hardness of the workpiece was measured by using FM800 micro hardness tester. Provided with the same electrical parameters, the surface roughness and hardness of the workpiece treated with red copper electrode was lower than that treated with graphite electrode. Provided that I=4.5 A and toN=30 μs, the average roughness values of the surfaces treated with red copper and graphite electrodes were 2.223 μm and 2.796 μm respectively, while the surface hardness values were 600HV and 700HV respectively. Provided that 1=9 A and toN=30μs, the average roughness values of the surface treated with red copper and graphite electrodes were 2.748 μm and 3.705 μm respectively, while the surface hardness values were 650HV and 750HV respectively. Under different electrode conditions, the surfaces of TC4 titanium alloy work-pieces machined by powder mixed EDM are all strengthened.