Study On Friction And Wear Properties Of Aluminum-based Bearing Materials With Bismuth

Aluminum-based sliding bearing alloy is a bearing material with light weight,high strength,good thermal conductivity,good corrosion resistance and friction and wear resistance which is widely used in mechanical,automotive,aerospace and other fields.Aluminum-tin alloy is a better bearing alloy with a comprehensive performance,concluding light weight,good anti-friction,wear resistance,compliance,imbedibility and a certain anti-occlusal ability,which is increasingly replacing the traditional copper based alloy and babbitt metal.In order to further develop the high specific strength and good tribological properties of aluminum-based bearings,and improve the bearing capacity and tribological properties of aluminum-tin alloy,the low melting point element Bi was added to the 2A12 matrix,and the mechanical and tribological properties of the 2A12 alloy with the Bi content of 0wt.%~8wt% were studied based on the previous studies.During the test,it is found that Bi is more susceptible to segregation in the aluminum matrix.It is unfavorable to study the friction and wear properties of the Al-based bearing alloy.In this paper,the preparation technology of the aluminum based bearing material is optimized,and the mechanical properties and tribology properties of the alloy were investigated,and the comparative study was carried out on the aluminum based alloy with Bi addition and Sn addition.The results show that the optimization of the casting process is favorable for the formation of homogeneous alloy,and when the melting temperature is 800℃,the cooling method is 100℃ water cooling,and the mechanical stirring speed is 200r/min,the organization shows better.The addition of low melting point element Bi reduces the mechanical properties of the material,but the degree of reduction is obviously lower than that of tin.With the increase of Bi content,the friction and wear properties of aluminum-based materials are obviously improved and the carrying capacity also correspondingly increased.Compared with the same content of tin-containing materials,Bi-containing materials have high strength and good tribological properties.The low melting point element Bi is similar to tin,which softens and melts and precipitates during the friction process,reduces the shear strength of the contact area,avoids the occurrence of adhesive tear,plays a better anti-friction and anti-adhesion effect.Moreover,the Bi-containing bearing material has better performance under the condition of step-by-step loading because the spherical structure of the Bi-rich phase has little separating effect on the matrix alloy,making the matrix alloy maintain good bearing capacity.