Abstract Lightweight and high strength materials are the primary requirements in the field of defense like in aircraft structures and aerospace applications. In this context, aluminum-based composites are one of the suitable choices because of its improved characteristics. In the present work, an attempt is made to develop aluminum (A359) based surface composites by incorporating the Si3N4 particles through friction stir processing (FSP). The numbers of FSP tool passes (single, two and three) are considered as variable parameters to evaluate its effect on various characteristics. The microstructural examination has been carried out by optical microscope and surface morphological analysis was done by scanning electron microscopy images. EDS with mapping images are used to observe the phase distribution and to identify the elements of the alloying and reinforcement materials. The elemental presences are also validated by X-ray diffraction and Raman spectroscopy. Further, mechanical properties like tensile test supported by fracture analysis and Rockwell hardness profile of the FSP zone are also discussed. In addition to it, the present work also an emphasis on the effect of the number of FSP tool passes on its wear resistance and thermal expansion. The results revealed that the value of maximum tensile strength and hardness were found to be 576 MPa and 125 HRB respectively in single pass FSPed composite. However, if the number of passes is increased then the maximum wear loss (11.7 × 10−3 g), maximum expansion due to heat (9 mm3) is observed at three-pass of FSP tool.

中文翻译：

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多道次搅拌摩擦加工制备A359/Si3N4表面复合材料的实验研究

摘要 轻质高强度材料是国防领域的主要要求，如飞机结构和航空航天应用。在这种情况下，铝基复合材料因其改进的特性而成为合适的选择之一。在目前的工作中，尝试通过搅拌摩擦处理 (FSP) 掺入 Si3N4 颗粒来开发基于铝 (A359) 的表面复合材料。FSP 刀具通过的次数（单次、两次和三次）被视为可变参数，以评估其对各种特性的影响。通过光学显微镜进行微观结构检查，通过扫描电子显微镜图像进行表面形态分析。带有映射图像的 EDS 用于观察相分布并识别合金和增强材料的元素。X 射线衍射和拉曼光谱也验证了元素的存在。此外，还讨论了机械性能，如断裂分析支持的拉伸试验和 FSP 区的洛氏硬度分布。除此之外，目前的工作还强调了 FSP 刀具通过次数对其耐磨性和热膨胀的影响。结果表明，单程 FSPed 复合材料的最大拉伸强度和硬度值分别为 576 MPa 和 125 HRB。然而，如果道次增加，则最大磨损损失 (11.7 × 10−3 g)，在 FSP 工具的三道次处观察到由于热引起的最大膨胀 (9 mm3)。