Influence of microstructures on mechanical properties of the Csf/Mg composite fabricated by liquid-solid extrusion following vacuum pressure infiltration

The short carbon fiber reinforced magnesium matrix composite (Csf/Mg) with a fiber volume fraction of up to 20 % was fabricated by liquid-solid extrusion following vacuum pressure infiltration (LSEVI) method. The effects of pressure (20, 30, 40, and 50 MPa) and temperature differences (515.9-590.7 degrees C) on the densifi-cation and precipitated phases of the composite have been fully investigated. Meanwhile, the tensile property and hardness were tested at different regions including the interface, the top, middle, and bottom regions of the prepared composite billets. The results show that an appropriate holding pressure can prevent shrinkage defects and decrease fiber aggregations. The hard and brittle Al8Mn5 phase was found near fibers and in the interfacial zone between the composite and the magnesium alloy. The phase and fibers together refine cc-Mg grains and enhance the mechanical properties of the composite. It has also been found that both the ultimate tensile strength (UTS) and the hardness peak in the middle region. Compared with the magnesium alloy matrix, the UTS and the hardness of the composite have been increased by 55.5 % (-213 MPa) and 97 % (-98 HV), respectively. Based on the present studies, the intrinsic relationship among the process parameters, microstructures, and performances of the Csf/Mg composite has been clarified.(c) 2022 Elsevier B.V. All rights reserved.