Hot-tearing of multicomponent Al-Cu alloys based on casting load measurements in a constrained permanent mold

Abstract

Hot-tearing is a major casting defect that is often difficult to characterize, especially for multicomponent Al alloys used for cylinder head castings. The susceptibility of multicomponent Al-Cu alloys to hot-tearing during permanent mold casting were investigated using a constrained permanent mold in which the load and displacement were measured. The experimental results for hot tearing susceptibility are compared with those obtained from a hot-tearing criterion based on temperature range evaluated at fraction solids of 0.87 and 0.94. The Cu composition was varied from approximately 5–8 pct. (weight). Casting experiments were conducted without grain refining. The measured load during casting can be used to indicate the severity of hot tearing. However, when small hot-tears are present, the load variation cannot be used to detect and assess hot-tearing susceptibility.