Effect of in-situ sub-micron sized TiB<inf>2</inf> reinforcement on microstructure and mechanical properties in ZE41 magnesium matrix composites

ZE41 Mg–TiB2 metal matrix composites with improved mechanical properties were synthesized via a novel processing route. In this process, the Ti–B system was developed without addition of third intermediate metallic Al powder, thereby preventing formation of any undesirable hazardous by-products from salt system (Al–K2TiF6–KBF4) and brittle TiAl3 intermetallic phase from master alloy (Al–Ti–B). Sub-micron sized TiB2 particles (5, 10 and 15 wt%) were reinforced in the ZE41-Mg alloy and the influence of TiB2 particles and its weight fraction on mechanical properties of composite materials were studied in details with an emphasis on microstructural characterization. The microstructural characterization shows reasonable uniform distribution of TiB2 particles in lower weight fraction of reinforcement and strong interfacial bonding with the matrix. A significant enhancement of the strength as well as grain refinement of composite were observed with increased TiB2 particles. The effect of TiB2 particle content on Young's modulus and yield strength was correlated via theoretical/mathematical modeling and experimental investigations. The strengthening mechanisms for strength enhancement of composites were established.