原位合成Al_(2)O_(3)/TiB_(2)颗粒混杂增强铝基复合材料的性能研究

Property study of Al_(2)O_(3)/TiB_(2) particle hybrid reinforced aluminum matrix composite by in-situ synthesis

针对传统铝合金无法满足工业和民用中对高强高导铝合金需求的问题,开发一种提升铝合金表面硬度且保证其导电导热性能的新型铝基复合材料。通过机械合金化法制备了Al-TiO_(2)-B混合粉末,采用放热弥散结合接触反应技术成功原位合成Al_(2)O_(3)/TiB_(2)颗粒混杂增强铝基复合材料,探究了原始粉末Al-TiO_(2)-B体系反应生成Al_(2)O_(3)/TiB_(2)颗粒混杂增强铝基复合材料的反应机理及反应温度对原位反应的影响,分析了铝基复合材料的微观组织形貌以及表面显微硬度和导电导热性能。XRD分析结果表明,反应温度达到1100℃保温200 min后,原始粉末Al-TiO_(2)-B体系中的TiO_(2)和B粉末完全反应,并且在反应过程中B粉抑制了中间产物Al3Ti和AlB2的生成,最终原位生成为Al_(2)O_(3)和TiB_(2)颗粒混杂增强的铝基复合材料。显微组织观察表明,在铝基体中原位生成了TiB_(2)颗粒(直径小于1μm)和Al_(2)O_(3)颗粒(粒径约为2μm),且铝基复合材料表面组织均匀致密。原位合成Al_(2)O_(3)/TiB_(2)混杂颗粒增强铝基复合材料的电导率为46.1%IACS,热导率约为198.5 W·m-1·K-1,显微硬度较传统A356铝合金的68 HV提升至76 HV,新型原位合成铝基复合材料在保证导电导热性能的前提下提升了铝基复合材料的显微硬度。

This study aims to develop a novel aluminum matrix composite material that enhances surface hardness while maintaining its electrical and thermal conductivity properties to meet the demands of industrial and civilian applications,given the inadequacies of traditional aluminum alloys.Through mechanical alloying,Al-TiO_(2)-B hybrid powders were prepared,and an in-situ synthesis of Al_(2)O_(3)/TiB_(2) particulate hybrid-reinforced aluminum matrix composite material was achieved using exothermic dispersion bonding contact reaction technique.The research investigates the reaction mechanism of the Al-TiO_(2)-B system to generate Al_(2)O_(3)/TiB_(2) particulate hybrid-reinforced aluminum matrix composite material and the influence of reaction temperature on in-situ reaction.Microstructural morphology,surface microhardness,and electrical and thermal conductivity properties of the aluminum matrix composite material were studied.XRD analysis revealed that at a reaction temperature of 1100°C and a holding time of 200 minutes,complete reaction of TiO_(2) and B powders in the Al-TiO_(2)-B system occurred,with B powder inhibiting the formation of intermediate products Al3Ti and AlB2 during the reaction process,resulting in the in-situ generation of Al_(2)O_(3) and TiB_(2) particulate hybrid-reinforced aluminum matrix composite material.Microstructural observation demonstrated the in-situ generation of TiB_(2) particles(diameter less than 1μm)and Al_(2)O_(3) particles(approximately 2μm in diameter)within the aluminum matrix,with a uniformly dense surface structure of the aluminum matrix composite material.The electrical conductivity of the in-situ synthesized Al_(2)O_(3)/TiB_(2) hybrid particle-reinforced aluminum matrix composite material was 46.1%IACS,and the thermal conductivity was approximately 198.5 W·m-1·K-1,with the microhardness increasing from 68 HV(for traditional A356 aluminum alloy)to 76 HV.This novel in-situ synthesized aluminum matrix composite material enhances microhardness while ensuring electrical and thermal conductivity properties.