Abstract
Frequently engineering students are introduced to materials in laboratory exercises that are isolated from each other. If these experiences can be connected, it provides an opportunity to begin to link the relationships between structure, processing and properties frequently modeled as the “Materials Triangle.” Currently the mechanical engineering materials labs: ENGR 45- Engineering Materials and ME 37-Manufacturing Processes, are separate. The objective of this study was to integrate sections of these labs using cast and wrought aluminum alloys to enrich the student education experiences by providing examples of the structure-property-processing relationship. To accomplish this goal, 2024 T3 wrought aluminum from the ENGR 45 tensile test lab and A356 cast aluminum from the ME 37 sand-cast lab were integrated into the microstructural analysis lab form ENGR 45. Microstructural analysis compares the grain and grain boundary structure of wrought aluminum with the dendrite and eutectic structure of cast aluminum. The 2024 T3 wrought aluminum had a grain size of 47 µm with the Brinell hardness range of 116-122. The A356 cast aluminum had an SDAS of 76 µm and Brinell hardness range of 35-74. The comparison of these alloys indicated that the dendrites have a coarser structure than grains which correlates with the decrease hardness. A visual comparison of the microstructures of two cast samples, a rectangular plate and cylinder piece, from a single casting show that one area of a casting has finer dendrites than other areas of the same casting. This various dendrite coarseness correlates with the range of average Rockwell F hardness being 37-79. These correlations are taught through worksheet questions in order to establish the concept of structure and property relationship.