(1. 青海大學(xué) 鎂技術(shù)工程研究所，西寧 810016；
2. 蘭州理工大學(xué) 甘肅省有色金屬新材料省部共建國家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 研究真空氣壓滲流法制備的硼酸鎂晶須增強(qiáng)鎂基復(fù)合材料(體積分?jǐn)?shù)30%)及其基體合金在液體石蠟潤滑條件下的滑動(dòng)摩擦磨損性能。試驗(yàn)條件為滑動(dòng)距離2 km，滑動(dòng)速度0·5、1.0、2.0、3.0和5.0 m/s，載荷5、10、18、25和40 N。結(jié)果表明：在潤滑條件下，引入增強(qiáng)相MgB2O5能提高復(fù)合材料在低載下的耐磨性能。隨著載荷的增加，復(fù)合材料的磨損由輕微磨損向嚴(yán)重磨損轉(zhuǎn)變。臨界載荷分別為：1 m/s，25 N；2 m/s，18 N；3 m/s，10 N；5 m/s，5 N。復(fù)合材料磨損情況的掃描電子顯微分析和觀察顯示，復(fù)合材料在兩種摩損階段的主導(dǎo)磨損機(jī)制分別為磨粒和剝層磨損。研究還發(fā)現(xiàn)，復(fù)合材料由輕微磨損階段向嚴(yán)重磨損階段的轉(zhuǎn)變不僅與載荷有關(guān)，還與滑動(dòng)速度有關(guān)。
關(guān)鍵字: 鎂基復(fù)合材料；晶須；磨損率；磨損機(jī)制
（. Institute of Magnesium Technology, Qinghai University, Xining 810016, China;
2. State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract: The liquid Paraffin-lubricated sliding tribological properties and wear behavior of Mg2B2O5 whisker reinforced magnesium matrix composites fabricated by vacuum-gas pressure infiltration process were investigated by using a pin-on-disc wear-testing machine against a GCr15 steel counterface under loads of 5−40 N, and within a sliding velocity range of 0.5−5.0 m/s for a constant sliding distance of 2 km. The results show that the transition load is found for a constant sliding velocity. When the loads are higher than the transition load, the wear rate increases sharply. The composites exhibit superior wear resistance compared with that of matrix alloy when the loads are below the transition load. The transition loads that are called critical loads in some literatures are 25, 18, 10 and 5 N for velocities of 1, 2, 3 and 5 m/s, respectively. The abrasive and delamination wear mechanisms are the dominant ones for loads above and below critical loads according to the SEM analysis of the worn surfaces and the subsurface of the composites. The crossover from abrasive wear mechanism to delamination wear mechanism of the composite is related not only with the loads but also with the sliding speeds.
Key words: magnesium matrix composite; whisker; wear mechanism; wear rate
