Study on the yield behavior of Al 2O 3–SiO 2(sf)/Al–Si metal matrix composites

Abstract

As the yield behavior of Al 2O 3–SiO 2(sf)/Al–Si MMCS is concerned, effects of heat treatment and parameters of short fiber, including volume fraction, size, distribution mode, were investigated. Dislocation configurations adjacent to interface between matrix and fiber were observed by TEM. Macro-yield stress ( σ 0.2) and micro-yield stress ( σ MYS) vary with parameters of short fiber, and effects of these parameters on σ 0.2 appear to be opposite to those on σ MYS. This phenomenon was interpreted by thermal residual stress in matrix and dislocation configuration. Suitable quenching followed aging treatment is an effective method to enhance the σ MYS and the σ 0.2 simultaneously. For the specimen with heat treatment of 550 °C/1 h WQ + 170 °C/6 h (T6) AC, σ 0.2 and σ MYS reach 200 and 58 MPa, respectively, and they are almost as twice as those as-cast.