Development of ceramic/Mg lamellar composites with superior high-temperature mechanical properties

The probe into development of lightweight magnesium matrix composites (MMCs) able to operate at high temperatures exceeding 300 °C is of vital importance in producing structural components in aerospace and automotive industries. In this work, a range of new lamellar ceramic/Mg composites were prepared via infiltrating molten Mg alloy into porous ceramic scaffolds. Due to the introduction of the specific microture, the composites showed excellent mechanical properties at temperatures above 300 °C. The high temperature mechanical properties of the new MMC are proportional to the ceramic content, enhancing the flexural strength from 197 MPa to 287 MPa at 300 °C, demonstrating a 45.69% increase. Additionally, as the test temperature increased, the flexural strength of the optimal composites rose firstly and then decreased, in which showed its maximum (407 MPa) at 200 °C. It delivered the flexural strength of 287 MPa at 300 °C, which was basically identical to that at 25 °C. It is worth mentioning that it has almost never been achieved in previous studies. The results of this research provide new design ideas and lay foundation for further investigation of the magnesium matrix composites capable of working at temperatures above 300 °C. •Different from the Mg-rare earth alloys, the ceramic/Mg lamellar composites were produced byMg alloy and porous scaffolds.•The microstructure and mechanical properties of the composites can be controlled by varying the parameters of the scaffolds.•The lamellar composites present superior elevated temperature mechanical properties than most of the commercial Mg alloys.•The 30 vol.% Si3N4 composites shows excellent high temperature bending strength: 407 ± 14 and 288 ± 1 MPa at 200 and 300 °C.