Anisotropy in aluminum castings—25 years on

摘要

The original paper by the authors, which was presented at the 1975 AFS Castings Congress, was entitled: "An Investigation of Anisotropy in Premium Quality Aluminum Castings." It described the determination of tensile properties in the circumferential and radial directions in a large ring-shaped casting, approximately 20 in. (500 mm) in internal diameter, poured in A357-T6. The casting was heavily chilled between large risers. The authors were curious as to how position and orientation of test samples affected strength and ductility in the location of the chill and near the risers. A follow-up paper, which appeared in the AFS Transactions in 1983, authored by Meyers, Saigal and Berry, returned to the same casting and examined the same properties in greater detail, attempting to relate them to the microstructural variation at different locations with respect to the chill casting interface. One of the principal challenges of the two studies was the problem of following property variations in close proximity, often as close as 0.50 in. (12 mm). This challenge was overcome by the use of a unique test technique, originally developed for the evaluation of the through-thickness properties of steel line pipe, known as the double ligament test (DLT). The results of the investigation are discussed in terms of subsequent developments in our understanding of the microstructural integrity of aluminum castings, especially through the recent work of Poirier, Caceres, Campbell and their respective coworkers.