| Abstract Scope |
Metal matrix composites are used in the tooling and mining industries for their hardness, fracture toughness, and wear resistance. Research at Missouri S&T is focused on improving the performance of tools used in friction stir welding (FSW) of steels, by employing co-extrusion to produce novel tools with engineered architectures. Co-extrusion offers a way to fabricate hierarchical architectures in composites, by co-extruding a core of one material (e.g., a ceramic) and a shell of a second material (e.g., a metal). Compositions being investigated consist of the following [core]-(shell) combinations: [WC/Co] – (Co), [WC/cBN/Co] – (Co), and [TiB2/SiC/B4C] – (W/Mo). The mechanical properties of each composition were evaluated for viability in FSW, including: flexural strength, hardness, wear resistance, and fracture toughness. Flexural strength and fracture toughness were also evaluated between 900°C and 1200°C in Ar atmosphere. Cylindrical pin FSW tools were machined and tested using both spot and linear welding methods. |