Microstructural and fractographic analysis of A359/Si3N4 surface composite produced by friction stir processing

Abstract High strength and lightweight materials are currently used in the automobile and defence sectors. In this framework, aluminium-based composites are a suitable choice due to their improved properties. The present study deals with the development of surface composites of A359/Si3N4 via friction stir processing. The varying percentage of reinforcement (2% to 6%) is the main criterion behind the study to observe its influence on mechanical, wear, thermal and corrosion properties. Investigations of microstructure and morphological characterization of the developed samples were conducted by optical light microscopy and scanning electron microscopy. Identification of the alloying elements, reinforcement materials and phase distribution is observed by EDS mapping. In addition, Raman spectroscopy and X-ray diffraction analysis were also conducted to validate the structural composition. As a research outcome, the effect of varying reinforcement percentage was examined on the tensile strength supported by fractographic analysis and hardness values. Apart from this, wear, thermal expansion and corrosion tests were conducted to assess the behavior of samples in different operation conditions. The results reveal the maximum tensile strength (478 MPa) and maximum hardness (119 HRB) with minimum wear loss (3.3 mg m–1), maximum thermal expansion (8.2 mm3) and maximum weight loss due to corrosion (0.0058 g) for A359/6%Si3N4 composite.