Preferred orientation and interfacial structure in extruded nano-Al3BC/6061 Al

To meet the increasing demand of high strength and lightweight, the novel platelet nano-Al3BC reinforcements with average thickness of 85 nm and width of 267 nm are in-situ incorporated into the 6061 alloy. The preferred orientation and Al3BC/Al interfacial structure are characterized after extrusion and their relationships with the properties are unveiled in this work. Microstructure characteristics reveal that Al3BC particles distribute in a preferred orientation: {0001}(Al3)BC//ED (Extrusion Direction), while alpha-Al also present similar rules: <110> // ND (Normal Direction); < 111, ED > = 4.5 degrees. The Al3BC/Al interface after extrusion is detected to be semi-coherently bonded with segregation of Fe, Si, Mg elements and the orientation relationship changes to (0001)(Al3BC)//(31 (1) over bar1)(Al), [11 (2) over bar0](Al3BC) [011](Al), which is divergent from our previous work without extrusion. According to the analysis, the changes are determined by preferred orientation distributions of platelet Al3BC particles and alpha-Al. Consequently, the preferred orientation and semi-coherent interface collectively contribute to the prominent enhancement of Al3BC particles on matrix alloy at both room and elevated temperatures. The maximum UTS of Al3BC/6061 composites at room temperature, 200 degrees C and 300 degrees C can reach up to 622 MPa, 445 MPa and 258 MPa, respectively.