アルミナ短繊維強化Mg-Nd合金の機械的性質

抄録

In order to improve the high temperature properties of an alumina short fiber reinforced magnesium alloy for automotive component application, an alumina short fiber reinforced Mg-Nd alloy, referred here to FRMg, has been developed by squeeze casting. The relation between its properties and metallurgical structure has been examined with the following experimental results. (1) The high temperature strength of FRMg with a sound metalluegical structure is superior to that of the matrix. (2) Mg₂Si precipitate produced by the reaction between the molten magnesium metal and silica binder in the fiber preform is preferentially present in the area where the molten magnesium metal finally infiltrates. (3) In the deformation of FRMg containing Mg₂Si precipitates, the fracture of Mg₂Si precipitates in contact with the fiber is observed in the heavily deformed matrix. (4) The properties of FRMg containing Mg₂Si precipitates scatter considerably, with some of them being inferior to those of the matrix. Examination of the metallurgical structure reveals, in the FRMg containing Mg₂Si precipitates, that Mg₂Si fractures at the beginning stage of plastic deformation because of the stress concentration induced at the precipitate/matrix interface and that this degrades the properties of FRMg.