A Study On Wear Behavior And Mechanism Of W-20Cu Composite Under High-temperature And High-speed Conditions

W-Cu composite was used as guide material of electromagnetic gun because of its superior performance, such as high hardness, excellent strength, good thermal conductivity. However, the materials were usually used in thermal, mechanical and electrical field coupling of harsh working conditions, and mechanical properties and microstructure evolution was directly related to the service life and service security of parts. Previous studies had focused on the preparation and electrical conductivity of W-Cu composite, while the friction and wear behavior of materials for W-Cu composite caused little attention. So the paper studied tribological behaviors,mechanism and microstructure evolution of W-Cu composite paired with 45 steel and7075 Al under the condition of dry friction of high temperature.In this paper, the effect of anneal process on W-20 Cu composite was discussed first. The anneal treatment carried on W-20 Cu composite were in the range of 750 ~950 ℃ and holding 0.5 ~ 6 h. When the anneal time was 1 h, the conductivity,hardness and density increased first and then decreased with temperature increasing.When the anneal temperature were 800 ℃ and 900 ℃, the conductivity decreased with the anneal time extension, the hardness increased first and then decreased with the annealed time extension, the related highest value of conductivity and hardness were47.32 %IACS at 800 ℃ × 0.5 h and l 285 HB at 900 ℃ × 1 h, respectively. The friction coefficient and wear rate of W-20Cu/45 steel after anneal process were lower than before. The lower friction coefficient appeared when the hardness difference was between 60 ~ 90 HB, the lowest value was 0.09. The wear mechanism of different annealed state W-20Cu/45 steel was oxidation wear and adhesive wear.The wear and friction test were took between W-20 Cu composite and 45 steel in the temperature range of 50 ~ 300 ℃. The friction coefficient increased first and then decreased with environmental temperature increasing. The wear rate increased dramatically when the temperature was beyond 200 ℃. The main wear mechanism of W-20Cu/45 steel were abrasive wear and oxidation wear at 100 r/min, and the main wear mechanism of W-20Cu/45 steel were fatigue wear, abrasive wear and oxidation wear beyond 100 r/min.Under the room temperature and the load with the rang of 400 ~ 800 N, the wear rate of W-20 Cu composite rised dramatically with the load rised while the wear rate of45 steel remained essentially unchanged. Lots of flaky wear debris peeled from W-20 Cu composite. The friction coefficient increased with the load increasing. Under the condition of heavy load, The wear mechanism of W-20Cu/45 steel were abrasive wear and spalling wear, and adhesive wear was complementary.The speed of high speed wear and friction test were in the range of 26 ~ 57 m/s.In order to better simulate the actual working condition, two materials were choosed,45 steel and 7075 Al. The wear mechanisms of W-20Cu/45 steel and W-20Cu/7075 Al were both adhesive wear and abrasive wear at high speed. The friction coefficient of W-20Cu/45 steel and W-20Cu/7075 Al were both increased and the wear rate of W-20 Cu composite reducing with the speed rising.