Tribological Properties Of Al-12%sn Alloy Prepared By Mechanical Alloying

Al-Sn based alloys are applied widely in the modern industry as sliding bearing materials. With the increase of revolution and load in modern automobile, the friction and wear properties of Al-Sn bearing alloy need to be improved further. Aluminum alloy with mid-tin has better anti-bite, and compliance and embedded possession, and its carrying capacity and anti-fatigue strength is higher than the high-tin aluminum alloy, and also can save valuable non-ferrous metals Sn, as a result of a competitive price. Therefore, mid-tin-aluminum alloy (Al-12% Sn) has been widely used in high-speed, high-pressure automotive engine. In this thesis, Al-12%Sn alloy was prepared by mechanical alloying (MA). Microstructure and tribological properties of MA Al-12%Sn alloy were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness test, and friction and wear test. In order to improve the tribological properties of MA Al-12%Sn alloy, investigate MA Al-12%Sn alloy added 30% raw powders.Al-12%Sn alloy powders after high energy ball milling, can obtain nano-composite structure. With the sintering temperature rising, Sn-phase grain size is gradually increasing, but still within 160nm. Sample density and micro-hardness decreased. When sintering temperature exceeds eutectic temperature, Sn phase part appears in a netlike distribution along the boundary of powder particles. However, there is much fine Sn-phase distributed uniformly in Al matrix. Found through the friction and wear testing, while in the 723K sintered alloy showed the best wear resistance capability. With the same composition of the sample compared with ball milling, MA Al-12% Sn alloy showed a higher carrying capacity and anti-friction, in high-load (150N) shows better wear resistance capability.MA Al-12%Sn alloy is added 30% raw powders which the size of is little big. Raw powders can be distributed uniformly in alloy. Sintering density is improved when MA Al-12%Sn alloy added 30% raw powders is compacted and sintered. There is also a part of Sn phase appearing netlike distribution when MA Al-12%Sn alloy added 30% raw powders is sintered above the eutectic temperature. Microhardness test shows that with the sintering temperature rising, the microhardness of MA Al-12%Sn alloy added 30% raw powders is gradually decrease and lower than MA Al-12%Sn alloy. Found through the friction and wear testing, while in the 823K sintered MA Al-12%Sn alloy added 30% raw powders showed the best wear resistance capability. Compared with MA Al-12% Sn alloy, P/M Al-12%Sn alloy and AlSn12Si2.5P1.7Cu, MA Al-12%Sn alloy added 30% raw powders showed the best wear resistance capability on 50～150N load. The friction coefficient of MA Al-12%Sn alloy added 30% raw powders is high on the 50N load. It is lower than the friction coefficient of P/M Al-12%Sn alloy and AlSn12Si2.5P1.7Cu, but higher than MA Al-12%Sn alloy.