Abstract:
With pure nickel, pure aluminum, pure niobium, pure carbon and 18Al-82V intermediate alloy as raw materials, Ni
3Al-Ni
3V-V
2C-AlCV
2 composite was prepared by vacuum melting. The microstructure, hardness,and friction and wear properties and wear mechanism in different atmospheres (air, oxygen and carbon dioxide) of the composite were studied and were compared with those of the Ni
3Al-Ni
3V alloy. The results show that the composite consisted of blocky Ni
3Al phase, network Ni
3Al+Ni
3V matrix phase, and in-situ generated V
2C and AlCV
2 phases. The hardness of the composite (550 HV) was higher than that of Ni
3Al-Ni
3V alloy (509 HV) due to the solid solution strengthening of some carbon and niobium dissolving in the Ni
3Al phase and Ni
3V phase, and the dispersion strengthening of the V
2C phase and AlCV2 phase formed by the other part of carbon and vanadium and aluminum. The average friction coefficient and wear rate of the composite in the air atmosphere were lower than those of Ni
3Al-Ni
3V alloy. The wear rate of the composite in the carbon dioxide atmosphere was the highest, followed by that in the air atmosphere, and in the oxygen atmosphere. The hardnesses of the wear surface of the composite in the air and oxygen atmosphere were similar, which were 706, 711 HV, respectively, and were higher than that in the carbon dioxide atmosphere (670 HV). The main wear mechanism of the composite was oxidative wear in the oxygen atmosphere, oxidative wear and fatigue wear induced by environmental embrittlement in the air atmosphere, and adhesive wear and abrasive wear in carbon dioxide atmosphere.