Research On Dry Sliding Friction And Wear Characteristics Of Al-20Si-5Cu Alloy

In this paper, the brake disc materials Al-20Si-5Cu as the research object. The effect ofheat treatment process on microstructure and hardness and dry sliding friction and wearcharacteristics of Al-20Si-5Cu alloy both been studied. At last, the means of SEM, EDS,OLS4000analysis room temperature and high-temperature friction and wear mechanisms ofmaterials. The results are as follows:The best heat treatment process of Al-20Si-5Cu:515℃solid solution of6hours, watercooled;165℃artificial aging of6hours, air-cooled. The heat treatment can improvemorphology of microstructure, and also effectively improve the micro-hardness of themacro-hardness of matrix.Study the effect of applied load on the ambient temperature tribological properties ofthe alloy Al-20Si-5Cu. The results show that solution and T6treatment can effectivelyimprove microstructure and hardness of materials. The wear rate of Al-20Si-5Cu alloy wasincreased with the increase of applied load. And the wear rate of T6treated samples islowest, so the wear resistence is best. But the friction coefficient varies with heat treatmentprocesses and has no sensitivity to applied loads, which varies in litter range and appearsstability. With the applied load change, the wear mechanism of the material also changed.The casting state materials from oxidative wear and abrasive wear changed intodelamination. The solid solution state and the T6state material from oxidative wear,abrasive wear into fatigue wear.Study the effect of sliding speed on ambient temperature friction and wear properties ofthe alloy: With the speed of change, the wear rate increases as the speed increases, but theT6state wear rate shown the lowest wear rate. Friction coefficient of different heattreatment state samples are in the small range of fluctuations, the T6state frictioncoefficient is the most stable, T6state material friction best performance. The T6statematerials have best wear resistance.At200℃, speed150r/min conditions, Studying the effect of applied load onhigh-temperature friction and wear properties of Al-20Si-5Cu alloy. The research resultsshow that: the wear rate of the samples increased with the applied load increasing, but theincreasing in the wear rate of the T6state materials is slow and small. So, the abrasionresistance of T6state sample is better. Meanwhile, the friction coefficient of the T6state material changed within a small area, and has less sharp peak compared to the casting statematerials, T6state material has good friction performance. With the increasing applied load,the wear mechanism of cast material is adhesive wear, the T6treated sample from abrasivewear changed into a slight adhesive wear.At applied load of4N and speed of50r/mim conditions, study the effect of temperatureon high-temperature friction and wear properties of Al-20Si-5Cu alloy: As the temperatureincreases, the wear rate increases, wear increased. And a critical temperature is existence.Before the critical temperature, the wear rate of the material slowly increased withtemperature increasing. After the critical temperature, the wear rate increased dramatically,but the critical temperature of the T6state materials than cast delayed50℃. Before200℃,the friction coefficient of the two state slowly increased with temperature increasing, butfriction coefficient variations T6state were smooth than the casting, fewer sharp peakappears. The friction properties of the T6state material is preferably. When the temperatureexceeds200℃, friction coefficient sharply increased, and the friction decreased stability.The wear mechanism also changed as the temperature increased. The casting and T6statematerials both from oxidative wear changed into adhesive wear. But T6state materials wearlight, under high temperature conditions, has good wear resistance.In conclusion, the variations in dry sliding frictional wear characteristics, which have aclose relationship with the effect of heat treatment on microstructure and hardness.