MICROSTRUCTURES AND MECHANICAL PROPERTIES OF SEMI-SOLID EXTRUDED IN-SITU Al-4.5Cu-0.8Mg/TiCpCOMPOSITES
(1.National Defence Key Laboratory of Metal Precision Heat Processing,School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China;
2.Department of Mechanical Engineering, Jiamusi University, Jiamusi154002, P. R. China)
2.Department of Mechanical Engineering, Jiamusi University, Jiamusi154002, P. R. China)
Abstract: A novel in-situ approach was used to prepare titanium carbide(TiC) reinforced Al based composites. The reacted, semi-solid extruded samples exhibited a homogeneous distribution of fine (0.1~1 um) TiC particles in a fine-grained Al-4.5Cu-0.8Mg matrix. The microstructures observed by TEM show that no reacted products were found in the interfaces between the matrix and the TiC particles, displaying that the interface cohesion strength is strong. The testing results have also shown thatσyandσbof the composites have been improved greatly, which are about 439 MPa and 549 MPa, increasing by 55% and 29%, respectively, compared with those of unreinforced alloy. The fracture morphologies observed by SEM show that they belong to a micro-ductility fracture, and that existence of coarse Al3Ti and segregation of TiC particles are also the causes of fracture.
Key words: microstructure mechanical property Al/TiCp fracture semi-solid extrusion