稀土强韧化MoSi_2材料的摩擦学性能

Tribological Behaviors of MoSi_2 Strengthened and Toughened by Rare Earth

采用高温自蔓延和真空烧结合成了含0.8%(质量分数)稀土/MoSi2复合材料。在MRH-5A型环-块摩擦磨损试验机上,考察了其与调质45#钢配对时的摩擦磨损特性。运用带有微探针的KYKY2800型扫描电镜分析了其磨损表面形貌,探讨了该材料的磨损机制。结果表明:在干摩擦同等条件下,稀土/MoSi2复合材料比纯MoSi2材料具有更好的抗磨损性能,其磨损率比纯MoSi2至少降低了68%。低速(200r/min)时,RE/MoSi2复合材料的磨损机制主要是粘着磨损,随着载荷的增加,粘着磨损脱落更为严重;在高速(400r/min)和低载荷(78N)下,RE/MoSi2复合材料的磨损机制仍以粘着磨损为主,在重载荷(274N)下,RE/MoSi2复合材料的磨损机制主要为粘着磨损和疲劳脆性断裂。

The MoSi2 matrix composite reinforced by mass fraction 0. 8% rare earth was prepared by self-propagating high-temperature systhesis （SHS） and high-temperature sintered. The wear properties of the composite against quenched and tempered steel were tested on a MRH-5 A type wear test machine. The wearing surface morphology of the composite was observed by using a KYKY2800 SEM with EDS and wear mechanism was discussed. The result shows that the RE/MoSi2 composite has better wear properties than simple MoSi2 under dry friction. The wear rate of the composite is 68% lower than that of the simple MoSi2. The wear mechanism of the RE/MoSi2 composite is mainly grain abrasion and slightly adhesive wear at low load. With load increasing, the lost of adhesive wear becomes much heavier. The wear mechanism of the RE/MoSi2 composite is mainly grain abrasion. The abrasion mechanism of the composite was adherence abrasion and brittle fracture with load increasing.