FATIGUE AND CREEP PROPERTIES OF Al-Si BRAZING FILLER METALS

The manufacturing process for automotive heat exchangers involves brazing using an aluminum brazing sheet. To ensure structural strength and improve durability, it is necessary to acquire mechanical properties for each of the materials. Al-Si alloys are most commonly used as the filler metal; however, the properties of the fillets formed by the solidification of the Al-Si filler melt have scarcely been reported previously. In this study, fatigue and creep properties of Al-10mass% Si cast alloy, which is considered to have the same chemical composition and metallic structure as those of the filler metal after brazing, were investigated. From the measured results of samples at various cooling rates during solidification, it was found the eutectic silicon particle size of the Al-Si alloy strongly related to these properties. These results showed that the finer silicon particles improved the fatigue and creep properties of fillets, even those with the same composition.