爆炸喷涂Al-Cu-Fe准晶涂层性能分析

Microstructure and Properties of Al-Cu-Fe Quasicrystal Coating Prepared by Explosive Spraying

目的提高准晶涂层内部准晶相含量,进而研究Al-Cu-Fe准晶涂层的各项性能。方法采用爆炸喷涂的方式在2A12铝合金基底上制备了Al-Cu-Fe准晶涂层。借助SEM、XRD等手段对Al-Cu-Fe准晶粉体的组织形貌、物相形成进行研究。采用显微硬度计、拉力试验机测试涂层的力学性能。采用比热容测试仪、激光热导仪检测涂层的热性能。使用摩擦磨损试验仪研究了涂层的摩擦磨损性能。结果水雾化法制成的Al-Cu-Fe准晶粉体主要包含准晶相和少量的β-Al_(42.54)Cu_(34.65)Fe_(22.81)相,准晶含量为73%。882℃为准晶相的熔点,粉体在800℃的退火温度下准晶含量能达到98.7%。涂层在700℃下比热容为0.749 J/(g·K),热导率为5.913W/(m·K)。涂层的显微硬度为569.4HV0.3,经退火处理最高硬度可达658.33HV0.3。涂层的结合强度为33.25 MPa,退火处理后结合强度为58.75 MPa。涂层在不同载荷和温度下,摩擦因数为0.768~0.512(均低于基体),在15 N和20 N的载荷下磨损率较基体提升明显(磨损率仅为基体的7.31%),高温环境下同载荷较室温环境下涂层的磨损率提升明显(高温磨损率为低温的3.00%)。结论准晶涂层可以对基体起到良好的热防护,对基体的减摩耐磨具有积极的作用。对涂层进行退火处理后,能有效提高涂层的硬度、结合强度等性能。

Quasicrystal material is a solid ordered phase with crystal structure between crystal and amorphous.It has both long-range quasi periodic translation order and amorphous rotational symmetry.Its special structure makes it outstanding in mechanics,tribology and heat insulation,and has a good application prospect in the field of medium temperature thermal protection.It has great application prospects in the surface protection of key moving parts such as aviation,ships and nuclear power.However,the content of quasicrystal phase in the quasicrystal coating has a great impact on its service performance.The retention of quasicrystal phase content is closely related to the spraying temperature.The energy of traditional plasma spraying and supersonic flame spraying is high,and the content of quasicrystal phase in the prepared coating is less than 40%.How to improve the content of high quasicrystal phase in the coating is an international problem.In this paper Al-Cu-Fe coating was prepared by explosive spraying.Firstly,Al-Cu-Fe quasicrystal coating was prepared on 2A12 aluminum alloy substrate,and then the coating was annealed.The powder morphology was observed by scanning electron microscope and the phase composition and quasicrystal content of Al-Cu-Fe quasicrystal powder were analyzed by X-ray diffraction.The mechanical properties of the coating were tested by microhardness tester and tensile testing machine.The thermal properties of the coating were measured by specific heat capacity tester and laser thermal conductivity tester.The friction and wear properties of the coating were studied by friction and wear tester.The results show that the Al-Cu-Fe quasicrystal powder prepared by water atomization mainly contains quasicrystal phase and a small amount of β-Al_(42.54)Cu_(34.65)Fe_(22.81)phase,the quasicrystal content is 73%.882℃ is the melting point of quasicrystal phase,and the quasicrystal content of powder can reach 98.7% at 800℃.The specific heat capacity of the coating is 0.749 J/(g·K)and the thermal conductivity is 5.913 W/(m·K)at 700℃.The microhardness of the coating is 569.4HV0.3.After annealing,the maximum hardness can reach 658.33HV0.3.The bonding strength of the coating is 33.25 MPa,and the bonding strength after annealing is 58.75 MPa.Under different loads and temperatures,the friction coefficient of the coating is between 0.768-0.512(both lower than the substrate).Under the loads of 15 N and 20 N,the wear rate of the coating is significantly higher than that of the substrate(the wear rate is only 7.31% of the substrate).Under the same load at high temperature,the wear rate of the coating is significantly higher than that under normal temperature(the wear rate at high temperature is 3.00% of that at low temperature).The quasicrystal coating can play a good role in thermal protection of the substrate,and also play a positive role in antifriction,wear resistance of the substrate.After annealing,the hardness,bonding strength of the coating can be effectively improved.