恒温扭动磨损腐蚀的模拟与试验

Simulation and Experimental Investigation of Tortional Wear Corrosion at Constant Temperature

为揭示材料在恒温液体介质中的扭动磨损腐蚀特性,研制了新型恒温扭动磨损腐蚀试验装置,并用该装置对Ti6Al4V合金在37℃的Saline溶液中的扭动磨损腐蚀行为进行研究.研究结果表明:在往复扭动角为±3°,法向载荷为50 N,频率为0.5 Hz的条件下,Ti6Al4V合金的摩擦扭矩曲线可分为初期很低、逐渐升高、然后略有降低和再升高逐渐趋于稳定的4个阶段;摩擦扭矩-角位移曲线包括直线型、椭圆型及平行四边形型.扭动后自然腐蚀电位迅速负移,然后逐渐正移并趋于相对稳定,稳定值低于扭动前;腐蚀电流则呈现先升高后降低并趋于相对稳定,稳定值高于扭动前.损伤是腐蚀与磨损耦合作用的结果.

In order to reveal the wear and corrosion characteristics of metal materials under torsional contact in liquid medium at constant temperature,a new device for torsional wear corrosion test was developed.Using the test system,torsional wear corrosion tests of Ti6Al4V were carried out in saline solution at 37℃ under a normal load of 50 N,a torsional angular displacement amplitude of ±3°,and a frequency of0.5 Hz.The results showed that the friction torque curves of the Ti6Al4V alloy in saline solution could be divided four stages： the friction torque was very low at first;it increased gradually to a peak value;after the peak,it decreased slightly;and then increased gradually to a relatively stable value at last.Three types of torques vs angular displacement curves in shapes of line,elliptical,and quasi-parallelogram presented during the tests.At the beginning of torsion,the free corrosion potential of the Ti6Al4V alloy had a rapid negative shift,followed by a slow positive shift to a relatively stable value lower than before torsion.Simultaneously,the corrosion current increased rapidly and then decreased to a relatively stable value higher than before torsion.The damage of Ti6Al4V alloy was typically caused by coupled wear and corrosion.