Interfacial and fracture behavior of short-fibers reinforced AE44 based magnesium matrix composites

摘要

Short fiber reinforced magnesium matrix composite was fabricated by infiltration with molten AE44 (Mg–4.0Al–4.1RE–0.3Mn) alloy. The microstructures in the interfacial region and matrix of composite were characterized using scanning electron microscopy, electron probe micro-analyzer and transmission electron microscope. The fracture initiation and growth was observed by in situ scanning electron microscopy. It was shown that the distribution of the alloying elements was affected by the addition of fibers. The SiO_2 binder in perform reacted with molten magnesium during infiltration, and the reaction product was identified as MgO. The Al–RE phases formed on the surface of fiber and in the matrix, in the form of lamella (Al_(11)RE_3) and particle (Al_2RE), respectively. Microcrack initiated in the region of interface of composites, further failure included interfacial debonding add fiber breakage mode or only fiber breakage mode, depending on the fiber distribution to the tensile stress direction.