微弧氧化对TC4钛合金微动磨损行为的影响

Evolution of Equiaxed and Lamellar α Phase during Heat Treatment of TA12A Titanium Alloy

摘要:

采用微弧氧化技术,在TC4钛合金表面制备高硬度氧化陶瓷层(MAO),对比研究了TC4钛合金基体与微弧氧化陶瓷层在2种不同位移幅值下的微动磨损行为。结果表明:位移幅值由80μm增大到150μm时,TC4钛合金基体微动损伤机制由粘着磨损和磨粒磨损转变为疲劳磨损和氧化磨损,而微弧氧化陶瓷层的损伤机制始终以氧化磨损为主;位移幅值为80μm时,TC4钛合金基体与微弧氧化陶瓷层磨损量均较小,而摩擦系数大且波动大;位移幅值为150μm时,两者磨损量出现不同程度的增大,而摩擦系数略有下降且趋于平稳;与TC4钛合金基体相比,微弧氧化陶瓷层的平均摩擦系数小,磨损轮廓浅,且磨损量仅为钛合金基体的70%。微弧氧化陶瓷涂层能够保护钛合金基体表面,有效改善TC4钛合金耐磨性。

Abstract:

With micro-arc oxidation technique,the high hardness ceramic oxide layer( MAO) was prepared on the surface of TC4 alloy,and the fretting wear behavior of TC4 alloy substrate and micro-arc oxide ceramic layer under two different displacement amplitudes was studied. The results show that,when the displacement amplitude increases from80 μm to 150 μm,the fretting damage mechanism of TC4 substrate changes from adhesive wear and abrasive wear to fatigue wear and oxidation wear,while the damage mechanism of micro-arc oxide ceramic layer is always dominated by oxidation wear. When the displacement amplitude is 80 μm,the wear amount of TC4 substrate and micro-arc oxide ceramic layer is small,but the friction coefficient is high and fluctuates greatly. When the displacement amplitude is150 μm,the wear amount increases to different degrees,while the friction coefficient decreases slightly and tends to be stable. Compared with those of TC4 alloy substrate,the average friction coefficient of micro-arc oxide ceramic layer is small,the wear profile is shallow,and the wear amount is only 70% of that of titanium alloy substrate. In summary,the results show that the micro-arc oxide ceramic coating can protect the surface of titanium alloy and effectively improve the wear resistance of TC4 alloy.