摩擦层的形成对TC4合金磨损性能的影响

Effect of the Formation of Tribo-Layer on the Wear Performance of TC4 Alloy

采用MG-2000型销盘式高温磨损试验机对TC4合金在环境温度为200、400和600℃,载荷为50~250 N时的磨损性能进行了研究.利用SEM、EDS、XRD以及XPS等对试样磨面和剖面的形貌、成分及结构进行了观察与分析.结果表明:在不同的试验条件下,磨损表面均会形成一层不同于基材的摩擦层.摩擦层的成分及分布形态对TC4合金的磨损性能产生了重要的影响.在200和400℃时,摩擦层分布不均匀且不含或仅含少量的摩擦氧化物,这样的摩擦层对磨损表面不具有保护作用,TC4合金的磨损率随着温度的提高而提高.在600℃时,摩擦层分布均匀,且摩擦层含有较多的Ti O2和Ti O摩擦氧化物,TC4合金的磨损率大幅下降.因此,磨损过程中形成的均匀且含有大量摩擦氧化物的摩擦层极大地改善了TC4合金的磨损性能.

The wear performance of TC4 alloy was investigated under the load of 50 ~ 250 N at the ambient temperature of200,400 and 600 ℃ by using MG-2000 type pin-on-disc high temperature wear tester. The morphologies,compositions and phase of worn surface and worn cross-section for the specimen were observed and analyzed by scanning electron microscopy,energy dispersive spectrometry,X-ray diffraction and X-ray photoelectron spectroscopy. The results show that tribo-layers,which chemical composition was different from the matrix,were formed on the worn surfaces. The composition and distribution of tribo-layer had an important impact on wear performance of TC4 alloy. At 200 and 400 ℃,the tribo-layer with no or trace tribo-oxides distributed unevenly and was not protective. Wear rate increased with an increase of the temperature. At 600 ℃,the tribo-layer of tribo-oxides Ti O2 and Ti O distributed uniformly and wear rate substantially decreased. Thus,the tribo-layer which was rich in tribo-oxides markedly improved the wear performance of TC4 alloy.