Determination of the size effect on the tensile properties of miniaturized specimens

To realize high-throughput tensile testing of miniaturized specimens, the size effect was investigated. High-throughput tensile testing was used to characterize the mechanical properties of steel in the micro-zone. Miniaturized specimens with diameters ranging from 0.7 mm to 2.5 mm were cut from low-alloyed steel and tested, and the deviations between the results of miniaturized and conventional sized specimens were examined. The results showed that the size effect was negligibly small for the tensile strength. However, the upper yield strength, lower yield strength, and plastic extension strength of miniaturized specimens decreased as the specimen diameter decreased. It was found that a diameter of 1.5 mm was critical for the tensile testing of miniaturized specimens. As the specimen diameter decreased toward 1.5 mm, the strength parameters gradually decreased, and as the specimen diameter further decreased from 1.5 mm, the strength parameters increased. In contrast, as the specimen diameter decreased from 1.3 mm, the elongation after fracture decreased. However, the percentage reduction of area did not vary between miniaturized and conventional sized specimens.