Effect of solution treatment time on tribological properties of Al-10SiM alloy
The application of biodiesel causes deterioration of the engine lubrication environment,accelerating the corrosion and wear of the commonly used piston material Al-10Si alloy,leading to early failure.Therefore,a new Al-Si alloy of Al10Si0.25Cu5Mg0.25Sn0.15Sc0.15Ti(referred to as Al-10SiM alloy)was designed and cast,and then subjected to 8 h,12 h,16 h and 20 h of solution treatment at 510 ℃ to study the effects of different solution treatment time on phase structure,microstructure,Vickers hardness and tribological properties under simulated biodiesel engine piston operating conditions of the Al-10SiM alloy.The results show that as the solution treatment time increases from 8 h to 20 h,the Mg2Si phase in the Al-10SiM alloy disappears,the Al3Sc and Mg2Sn phases first form and then disappear,the size of the precipitated phases first decreases and then grows,and the distribution and uniformity of the precipitated phases first improve and then deteriorate.The Vickers hardness of the alloy reaches its highest value of 162.6 HV after solution treatment for 16 h,and then decreases to 130.8 HV after solution treatment for 20 h.Under normal loads of 10 and 15 N,the friction coefficient and wear rate of the Al-10SiM alloy decrease when the solution treatment time is 8-16 h,and increase again when the solution treatment time is 20 h.The best friction reduction and wear resistance performance is achieved when the solution treatment time is 16 h,and they all exhibit varying degrees of adhesive wear,abrasive wear and fatigue wear during friction.
Al-10Si alloysolution treatmentprecipitated phasetribological propertypiston material
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