不同滑动速度下两种钛合金的磨损行为

Dry sliding wear behavior of TC4 and TC11 alloys at various sliding velocities

采用销-盘式磨损试验机对比研究两种典型双相钛合金TC4和TC11合金在不同滑动速度下的磨损行为,并探讨了磨损机制。结果表明:TC4合金的磨损率随滑动速度加快和载荷增加而增长,滑动速度为4m/s时,同载荷下的磨损率达到了最高值;而TC11合金的磨损率随滑动速度加快先增加,在滑动速度为2m/s时达到最高值然后开始下降,在4 m/s时取得最低值。载荷30 N时,TC4合金在滑动速度为1~4 m/s时的磨损机制主要为轻微粘着磨损、磨粒磨损和剥层磨损;TC11合金在滑动速度为1~2 m/s时的磨损机制为轻微粘着磨损、磨粒磨损和剥层磨损,在3 m/s时的为氧化磨损和磨粒磨损,但在4 m/s时的为氧化轻微磨损。两种钛合金在滑动速度为1~2m/s时的磨损行为与磨损机制相似。但高速下,稳定摩擦氧化物层的存在显著降低了TC11合金的磨损率;而TC4合金由于硬度相对较低,对摩擦氧化物层的支撑作用不足,磨损率快速增长。

Dry sliding wear behaviors of TC4 and TC11 duplex alloys were comparatively studied at various sliding velocities on a pin-on-disc tester. The wear mechanisms were also discussed. The results show that the wear rate of TC4 alloy increases with increasing the load and sliding velocity, and then reaches the maximum value at 4 m/s under an identical load. For TC11 alloy, the wear rate firstly increases as a function of sliding velocity, obtains the climax at 2 m/s, then gradually decreases at 3 m/s, and ultimately acquires the minimum value at 4 m/s. For TC4 alloy, the mild adhesion, abrasion and delamination prevails at 1-4 m/s. However, the main mechanisms for TC11 alloy were mild adhesive, abrasive and delamination wear at 1-2 m/s, oxidative and abrasive wear at 3 m/s, and oxidative mild wear at 4 m/s. By contrast, two alloys share the similar wear behaviors and mechanisms at 1-2 m/s. But at a high sliding velocity, the existence of a stable tribo-oxide layer is responsible for the reducing wear rate of TC11 alloy. For TC4 alloy, the rapidly increasing wear rate can be attributed to the low hardness and insufficient support on tribo-oxide layer from the substrate.