Research Of The Friction And Wear Behaviors Of MoSi₂ At Elevated Temperature And Forecasting Model

Intermetallic compound MoSi₂ has double characteristics like metal as well as like ceramic. It has better performance such as hardness, intensity, elasticity coefficient, heat and electricity conduction. At present, the material of MoSi₂ have used widely in element for heating. It is used as the structural material which work in high temperature above 1000℃has become the hot spot of researching. Through widely studying of the tribological properties, scholars find that the MoSi₂ has better wear resistance, but most of the works are done at room temperature, none of them study the wear behaviors of MoSi₂ upon 800℃. In this paper, the tribological properties of molybdenum dislicide (MoSi2) against Al₂O₃ upon 700℃are investigated.The MoSi₂ composites have been synthesized by Self-propagating High temperature Synthesis (SHS) and high temperature sintering technique. The tribological properties of molybdenum dislicide (MoSi₂) against Al₂O₃ are carded on an XP-5 type High Temperature Friction and Wear Tester. The wear mechanisms are analyzed by micrographs of the surface observed by SEM with EDS. A RBF network forecasting model for wear rate is built with a workbox of artificial neural network. Results are shown as the following:1. The tribological properties and wear mechanisms of molybdenum dislicide were influenced greatly by load. At the condition of 1000℃,60rpm, MoSi₂ has better wear resistance when load was lower than 50N, adhesion exists widely in this experience. However, with the load increasing, the wear mechanisms of MoSi₂ are changed from abrasion, plastic forming to fatigue fracture in turn.2. The tribological properties and wear mechanisms of molybdenum dislicide were influenced greatly by temperature. At the condition of 30N, 60rpm, MoSi₂ has well friction and wear property below 800℃. The main wear mechanisms of MoSi₂ are adhesion and oxidation at high temperature. When over 900℃, because the brittle ductile transition temperature (DBTT) of MoSi₂ is about 900℃, plastic deformation and fracture are found on the worn surface of MoSi₂.3. The tribological properties and wear mechanisms of molybdenum dislicide were influenced greatly by rotary rate. At the condition of 1000℃, 30N, MoSi₂ has well friction and wear property below 80rpm. At different rotary rate, the main wear mechanisms of MoSi₂ are adhesion. However, with the rate increasing, plastic forming and abrasion also exist.4. A forecasting model of wear rate for MoSi₂ was built with artificial neural network, it has better forecast under different temperature, load and rotary rate.