Fabrication and properties of in situ synthesized particles reinforced aluminum matrix composites of Al–Zr–O–B system

Abstract

A new in situ Al–Zr–O–B system is exploited. The Al–Zr(CO3)2–KBF4 components are used to fabricate the particle reinforced aluminum matrix composites by the direct melt reaction method. The analytical results of XRD and SEM show that the in situ endogenetic particles are ZrAl3, ZrB2 and Al2O3, which are well distributed in the aluminum matrix. The sizes of reinforced particles are 0.5–2.5 μm. The results of mechanical properties of the composites show that the tensile strength and yield strength are improved with the increase of theoretical volume fraction of particles in matrix in the range of 0–12%, which are much superior to those of aluminum matrix. The best elongation of composites is 33% when the theoretical volume fraction is 3%. The fracture mechanism belongs to a ductile one. The wear resistance properties of the composites are much higher than that of aluminum matrix. The best abradability is got when the theoretical volume fraction of particles is 6%. The wear mechanism of the aluminum matrix is adhesive wear while the wear mechanism of (ZrAl3 + ZrB2 + Al2O3)p/Al composites is abrasive wear.