Thermal Sprayed Aluminum Coatings Al99 and AlSi12 on Carbon Fiber Reinforced Magnesium-Alloy AZ91 for Integration in Aluminum-Cast Processes

Aluminum castings have limited strength and stiffness and tend to exhibit brittle fracture behavior under fatigue loading. These properties can be significantly improved, however, as this study shows, by reinforcing cast aluminum parts with magnesium metal-matrix composite structures. In order to obtain a bond between the cast Al and fiber-reinforced Mg composite surfaces, Al alloy (Al₉₉ and AlSi₁₂) layers were deposited on the Mg structures by thermal spraying. The mechanical properties of the bonding were assessed via single-lap shear and adhesive tensile tests along with optical microsection analysis. Hybrid aluminum alloy AlSi₁₀Mg castings incorporating coated Mg-MMC inserts were also produced and examined, validating the general approach, while revealing that heat input to the MMC structure must be reduced through design or process adaptations.