新型Ni3Al/石墨高温固体自润滑材料的制备及其性能

采用熔炼法, 制备出新型Ni3Al/石墨抗高温、耐腐蚀固体自润滑材料.结果表明: Al不仅是强化合金基体的元素, 而且是一种使片状石墨转变为球状石墨的球化剂; 铝与氧结合成渣降低了氧在石墨表面的吸附.建立了界面能和过冷度对石墨生长形态影响的动力学模型; 分析表明, 石墨在洁净的液态金属中结晶, 由于(1010)棱面与(0001)基面的温度回升速率的差异, 促使石墨球状生长.石墨经球化处理后, 材料的冲击韧性得到提高; 将该材料与GCr15轴承钢及45﹟退火钢进行干摩擦磨损时, 摩擦因数分别为0.36和0.40.

Preparation and properties of high-temperature self-lubricating Ni3Al/graphite alloy

A new high-temperature self-lubricating Ni_3Al/graphite alloy was produced by melting method. The results show that Al element is not only an element that strengthens the alloy matrix, but also a nodularizer that promotes the transition from flaky graphite to spheroidal graphite. The combination of Al and oxygen decreases the absorption of oxygen on graphite surface. A dynamic model about the influence of interfacial energy and undercooling on the growth morphology of graphite has been established. The analysis show that during the crystallization of graphite in clean liquid metal, the difference of temperature recovery rate between (1010prismatic plane and (0001basal plane promotes the growth of spheroidal graphite. After the graphite being spheroidized, the impact toughness of the alloy was improved. Through dry friction and wear experiment against GCr15 bearing steel and 45~# annealed steel, it was found that the friction coefficient of the alloy remains stably as 0.36 and 0.40, respectively.