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磨擦加工技术(FSP)细化铝合金表面涂层组织及增强结合强度的机制采用无针搅拌头对7075铝合金表面热喷涂铝基Al_2O_3-TiB_2涂层进行搅拌摩擦加工。通过SEM分析了搅拌摩擦加工前后涂层的组织,粘结拉伸法测试了涂层搅拌摩擦加工前后的结合强度。应用ABAQUS有限元软件模拟分析搅拌摩擦加工过程中的温度场和应力场。结果表明,搅拌摩擦加工过程,涂层加工区域的温度达到500℃以上,应力超过330 MPa,涂层发生了剧烈的热机械变形,产生动态再结晶,使原始组织中孔洞、间隙和裂纹等缺陷消失,形成细小的新晶粒。涂层和基体间由于剧烈的热机械变形产生固相焊合,结合强度由5.2 MPa提高到48.6 MPa。
Friction processing technology (FSP) Mechanism of refining microstructure and bonding strength of aluminum alloy surface The friction stir processing of aluminum-based Al 2 O 3 -TiB 2 coating on 7075 aluminum alloy was carried out by using a needleless mixing head. The microstructure of the coating before and after the friction stir processing was analyzed by SEM. The bond strength before and after the friction stir processing of the coating was tested by the bonding and stretching method. ABAQUS finite element software was used to simulate the temperature field and stress field in friction stir processing. The results show that during the process of friction stir processing, the temperature in the processing area of the coating reaches over 500 ℃ and the stress exceeds 330 MPa. The coating undergoes severe thermo-mechanical deformation and produces dynamic recrystallization. The defects such as voids, gaps and cracks in the original structure Disappear, the formation of small new grains. Solid-phase welding occurred between the coating and the substrate due to severe thermo-mechanical deformation, and the bonding strength increased from 5.2 MPa to 48.6 MPa.