In this study, by friction stir processing, we fabricated several defect-free Al7075/B₄C/TiB₂ mono and hybrid surface composites containing various amounts of B₄C and TiB₂ reinforcements with high quality interfacial bonding with substrate, fine recrystallized matrix grains, and homogenous dispersion of ceramic particles through the matrix. The composite region of hybrid composite samples was more constricted compared with that of mono composite samples. All hybrid composites had more hardness and wear resistance in comparison to Al/B₄C mono composite sample. Among different hybrid composites, the most optimal dispersion of ceramic particles, minimum size of B₄C and TiB₂ ceramic particles, the lowest friction coefficient, and the highest hardness and wear resistance belonged to the hybrid composite containing equal weight percentage of B₄C and TiB₂ ceramic particles (named 50%B₄C-50%TiB₂ hybrid composite). The hardness and wear resistance of the Al7075/B₄C, Al7075/TiB₂ mono composites and the 50%B₄C-50%TiB₂ hybrid composite were respectively enhanced by (91%, 121%, 107%) and (67%, 82%, 87%) regarding Al7075 base alloy. During wear, an unstable-simple tribolayer was formed on the surfaces of Al7075 base alloy and unreinforced FSPed samples; however, a more stable mechanically mixed tribolayer containing a mixture of oxygen, ceramic particles, and alloying elements of Al7075 base alloy and steel counterface was formed on the surface of the composite samples. The most stable tribolayer with the highest self-lubricating behavior belonged to the 50%B₄C-50%TiB₂ hybrid composite owing to the high amount of iron and very low amount of B₄C in the tribolayer, resisting the subsurface of tribolayer to crack propagation.

在这项研究中，通过摩擦搅拌工艺，我们制造了几种无缺陷的Al7075 / B ₄ C / TiB ₂单层和混合表面复合材料，其中包含各种数量的B ₄ C和TiB ₂增强材料，并与基材，精细的重结晶基体形成了高质量的界面结合。颗粒，并通过基体均匀分散陶瓷颗粒。混合复合样品的复合区域比单复合样品的区域更狭窄。与Al / B ₄ C单复合材料样品相比，所有杂化复合材料均具有更高的硬度和耐磨性。在不同的混合复合材料中，陶瓷颗粒的最佳分散，B ₄ C和TiB的最小尺寸₂陶瓷颗粒中，摩擦系数最低，硬度和耐磨性最高的杂化复合材料均包含相等重量百分比的B ₄ C和TiB ₂陶瓷颗粒（称为50％B ₄ C-50％TiB ₂杂化复合材料）。Al7075 / B ₄ C，Al7075 / TiB ₂单晶复合材料和50％B ₄ C-50％TiB ₂的硬度和耐磨性与Al7075基合金相比，杂化复合材料分别提高了（91％，121％，107％）和（67％，82％，87％）。在磨损过程中，Al7075基合金和未增强的FSPed样品的表面形成了一个不稳定的简单摩擦层。然而，在复合样品的表面上形成了一种更稳定的机械混合摩擦层，该摩擦层包含氧气，陶瓷颗粒以及Al7075基合金和钢对面的合金元素的混合物。具有最高自润滑性能的最稳定的摩擦层属于50％B ₄ C-50％TiB ₂杂化复合材料，这是由于摩擦层中的铁含量很高且B ₄ C含量极低，可抵抗摩擦层的表面裂纹扩展。