Microstructure and creep behaviour of magnesium hybrid composites

A comparison is made between the creep characteristics of the unreinforced squeeze-cast AZ91 and QE22 magnesium alloys and their hybrid composites reinforced with 7 vol.% short carbon fibres and 15 vol.% SiC particulates. Although the creep resistance of the reinforced AZ91 alloy is considerably improved by comparison with the unreinforced matrix alloy, no beneficial effect of hybrid reinforcement on the creep resistance of QE22 was found. A detailed microstructural evaluation of the materials was performed. It was possible to relate the creep results to the microstructural features.