Microstructure elaboration and mechanical properties of AlNp/4032Al composite
(1.黑龙江省哈尔滨市哈尔滨工业大学材料科学与工程学院2.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China3.Center for Composite Materials, Harbin Institute of Technology, Harbin 150001, China4.School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: A dense and uniform 50%AlNp/4032Al(Al-12%Si) composite was fabricated by squeeze casting process that involved pressure infiltration of molten 4032Al into a porous AlN preform. TEM observations show that there are high densities of dislocations in the aluminum, and these thermally induced dislocations are attributed to the difference of coefficients of thermal expansion between AlN and aluminum. The Si phases in the matrix are found to preferentially nucleate around AlN particles, and the reasons influencing heterogeneous nucleation of Si on AlN are discussed. The composite exhibits excellent mechanical properties, with a Brinell hardness of 268 and a bending strength of 556MPa. The modulus of AlNp/Al composite reaches 145GPa and agrees well with the prediction by Hashin-Shtrikman model.
Key words: AlN； aluminum matrix composite； microstructure； mechanical property