Comparison of Stress–Strain Properties from Profilometry-Based Indentation Plastometry (PIP) and Conventional Tensile Testing

Abstract

Profilometry-based indentation plastometry (PIP) was studied in this research to obtain stress–strain data from a simple indentation test. Five alloys commonly produced by additive manufacturing, Ti6Al4V, Ahead CP1, AlSi10Mg, Ni625, and Ni718, were used to print tensile bars using laser powder bed fusion (L-PBF). The tensile bars were then tested using the ‘gold standard’ of mechanical testing, conventional tensile methods outlined in ASTM E8. The tested tensile specimens were then sectioned through the grip section and polished using standard metallographic preparation techniques and PIP tested. When comparing the two test methods, the average tensile strength between all the materials showed a difference of 3.2% while the yield strength differed by 3.7%. These small differences between testing methods demonstrate that PIP testing is a viable alternative to the tensile test. Particular attention was given to the variation in the PIP-determined properties, and the origins of this variation are discussed. A test method standard is currently being developed for this methodology through the ASTM F42 committee, and therefore independent data to assess the precision and accuracy of the method are required.