Microstructure and material soundness in liquid and rheocast AM50 and effect of section thickness.

Commercial grade AM50 magnesium alloy was dlecast to varying wall thickness using both the RheoMetal process and conventional liquid casting. The resulting microstructure and pore structure were analysed. The rheocast material had larger pores than the conventionally cast material, scattered over the central 50% of the cross-section, while the pores in the conventionally cast material was concentrated to a segregation band at a depth corresponding to approximately 30% of the wall thickness. In the Rheocast samples, there was a correlation between thicker sections and larger primary a-Mg globules with a lower shape factor. [ABSTRACT FROM AUTHOR]