NiAl-7.5Cr-2.5Ta-5Co合金的室温摩擦磨损性能

Friction and Wear Properties of NiAl-7.5Cr-2.5Ta-5Co Alloy at Room Temperature

采用往复摩擦磨损试验方法,研究了不同接触变形状态和摩擦热效应下Ni Al-7.5Cr-2.5Ta-5Co合金的磨损性能与机理。结果表明:弹性接触状态下,变形区域的弹性应力松弛所引起的微小移动可破坏形成的金属结点,其摩擦系数较低;塑性接触状态下,合金磨损表面发生粘着-剪切特征,其摩擦系数较高;随着摩擦热效应的增强,合金摩擦表面自生成的Ni和Co的氧化物膜增多,降低了合金的摩擦系数,当P m·V值大于865 350(N/s·mm)时,合金的摩擦系数小于0.3,表现出良好的自润滑特性。

The wear properties and mechanism of Ni Al-7.5Cr-2.5Ta-5Co alloy were investigated in different conditions of contact deformation and friction thermal effects. Results show that under the 10 N loading condition, the Ni Al-7.5Cr-2.5Ta-5Co alloy is at resilient contact state, and it can offer lower friction coefficient as a result of its tiny motion caused by the elastic stress relaxation of deformation areas which damages the metal bonding. Under the 45-115 N loading condition, the friction coefficient of the alloy increases resulting in its significant adhesion shear phenomenon brought about by the formation of metal nodes between Ni Al-2.5Ta-7.5Cr-5Co and Si3N4 during the process of friction and wear. With the increase of P m·V, the friction coefficient gradually decreases with more oxide layers of nickel and cobalt generated by itself on friction surface, which partially eliminate the contact of alloy and Si3N4. The cobalt element improves the strength and hardness of Ni Al-7.5Cr-2.5Ta alloy, and also plays an important role in reducing the friction coefficient of Ni Al based alloy.