| The reinforcement of an Al casting with ferrous inserts (hybrid systems) through a joining technique to utilize both Al alloys (lightness) and Fe-based alloys (stiffness) is of interest, especially in the transportation sector. This work focuses on different technological aspects of cast joining of cast iron to an Al alloy using an intermediate material (or coating).Decarburization, flux treatment, suitable coating, and optimizing the process parameters improved the joint properties. Combination of "McGill 2" coating alloy and 1 min immersion time (in the Al melt) resulted in the formation of an Al-Fe joint with optimized characteristics. The results showed that the cast joining could be used to strengthen the Al castings and improve their performance.The experimental set up consisted of preparing the insert surface followed by coating the insert, and then, immersing it into an Al melt, and allowing the system to cool down to room temperature. The effects of flux treatment, decarburization, and the coating application, as well as the immersion time in the Al melt on the Al-Fe joint quality were investigated. The microstructure evolution of the reaction layer forming at the insert-coating interface was determined as a function of the coating time and the coating composition, and their effects on the joint properties were evaluated. The relationship between the microstructure and microhardness of the joint zone was established. |
