Microstructure characteristics and their effects on fatigue behaviors of the bond zone between Al‐12Si/ABOw composites and Al‐12Si alloys

Abstract In order to research the fatigue properties of the bond zone between aluminum borate whiskers (ABOw)‐reinforced composites and matrix Al‐12Si alloys, specially designed specimens consisted of Al‐12Si/ABOw composites and Al‐12Si alloys (named C/A specimen for short) were used in fatigue tests at different temperatures. The microstructure evolution of the bond zone of C/A specimen was studied through electronic microscope analysis. The results showed that the aluminum borate whiskers could cause segregation of alloying elements in the Al matrix and formation of numerous microscopic pores. Moreover, whiskers that were perpendicular to the load tended to cause interface between whiskers and Al matrix or Si particles cracking and thus lead to deterioration of fatigue performance. With the change of temperature from 25°C to 350°C, the toughness of Al matrix increased and the strength decreased, which also made the most serious stress concentration site of C/A specimen varied at different temperatures.