ABSTRACT The multi-pass mode friction stir processing (FSP) was applied to Al-30%Mg2Si in-situ composite under optimised conditions. Also, the influence of the pass number increase was evaluated on microstructure and dry sliding wear behaviour of composite at room temperature (RT) and High temperature (HT, 200ᵒC). The optimal RT wear test results were achieved in the three-pass processed (3P) sample.Furthermore, elevating the wear test temperature increased the wear rate and the ACOF of the as-cast composite, compared with RT condition. Nevertheless, covering the worn surface of the FSPed sample by fragmented and evenly distributed Mg2Si particles and improved hardness (specifically in 2P and 3P samples) prevented the severe mass loss in FSPed samples and enhanced the HT wear resistance of Al-30Mg2Si composite. The active wear mechanisms of the as-cast and FSPed composite were also studied at both RT and HT conditions.

中文翻译：

---

搅拌摩擦加工Al-30Mg2Si复合材料的高温摩擦学性能

摘要 在优化条件下，将多通道模式搅拌摩擦加工 (FSP) 应用于 Al-30% Mg2Si 原位复合材料。此外，还评估了通过次数增加对室温（RT）和高温（HT，200ᵒC）下复合材料的微观结构和干滑动磨损行为的影响。在三道次加工 (3P) 样品中获得了最佳的 RT 磨损试验结果。此外，与 RT 条件相比，提高磨损试验温度会增加铸态复合材料的磨损率和 ACOF。然而，通过破碎且均匀分布的 Mg2Si 颗粒覆盖 FSPed 样品的磨损表面并提高硬度（特别是在 2P 和 3P 样品中）防止了 FSPed 样品中严重的质量损失并提高了 Al-30Mg2Si 复合材料的高温耐磨性。