This paper reports on the effect of ZrB2 and hBN solid lubricant particles on the dry sliding wear behaviour of the AA7075 composite, fabricated by stir-squeeze cast technique. ZrB2 and hBN at levels of 5 wt% were chosen as reinforcements for the study. The optical microscope images revealed uniform distribution of particles and a low order of porosity in microstructure, possibly due to the squeeze pressure. The ZrB2 particles reinforced composite (AZ) showed an improvement in hardness compared to as-cast (A0) and hBN containing composite (AH). A minor reduction in the hardness of ZrB2–hBN hybrid composite (AZH) was observed. This is attributed to changes in the hardness induced by the individual ZrB2 and hBN particles. The hybrid composite (AZH) exhibits a superior wear resistance, possibly due to the formation of good quality B2O3 and H3BO3 self-lubricating film.

中文翻译：

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ZrB2/hBN颗粒对搅拌挤压铸造法制备的AA7075复合材料磨损行为的影响

本文报告了 ZrB2 和 hBN 固体润滑剂颗粒对通过搅拌挤压铸造技术制造的 AA7075 复合材料的干滑动磨损行为的影响。选择 5wt% 的 ZrB2 和 hBN 作为研究的增强剂。光学显微镜图像显示颗粒分布均匀，微观结构中孔隙率较低，这可能是由于挤压压力所致。与铸态 (A0) 和含 hBN 的复合材料 (AH) 相比，ZrB2 颗粒增强复合材料 (AZ) 的硬度有所提高。观察到 ZrB2-hBN 混合复合材料 (AZH) 的硬度略有降低。这归因于由单独的 ZrB2 和 hBN 颗粒引起的硬度变化。混合复合材料 (AZH) 具有优异的耐磨性，