Enhancing the toughness of Wf/W composites by modifying the fiber/matrix interface utilizing AlN-covered Wf

Abstract

In this study, short tungsten fibers (Wf) were covered with AlN to modify the fiber/matrix interface in short tungsten fiber-reinforced tungsten matrix composites (Wf/W) fabricated by Fe-activated sintering. During the densification process, an intact and continuous AlN interlayer formed at the fiber/matrix interface through the effective sintering of the AlN powders covering the Wf surface. The AlN interlayer stably existed between the fibers and the matrix without any significant interfacial reactions, leading to relatively weak bonding at the fiber/matrix interface. Based on the extra energy dissipation mechanisms, the composite exhibited typical pseudo-ductile behavior and an increase of 80.35 % in fracture toughness compared to the W(Fe) material. The pseudo-ductile behavior increased the fracture surface area and reduced the stress intensity at the crack tip, resulting in a remarkable toughening effect on the composite.