Predicting Flow Curves of Q&P Steel Using Sharp Pyramidal Nanoindentation on Constituent Phases: Isostrain Method

Abstract

In this research, a method is presented for predicting macroscopic plastic flow behavior of a quench and partitioning (Q&P) steel using data of nanoindentation experiments.The method is based on Tabor’s model in which nanohardness values obtained with indenters of different angles to be connected to the flow behavior of the indented material. The process consists of two steps: (i) the macroscopic flow relation of each microphases assessed based on the characteristic strain and constraint factor, (ii) the total flow curve of the steel extracted through an isostrain manner. A rationally successful prediction of the macroscopic plastic flow of the Q&P steel is obtained from the constituent phases properties due to consideration of the indentation size effect and application of a rule of-mixture. Eventually, the accuracy of the estimation is verified by comparing the predicted stress-strain curve to the tensile curve obtained from a standard bulk sample.

Toward an Instrumented Strength Microprobe – Origins of the Oliver-Pharr Method and Continued Advancements in Nanoindentation: Part 2

“…Furthermore, Yang et al also utilized statistical data analysis to quantify the transformation kinetics of bainite phase formation within an austempered steel [40]. Still, nanoindentation for such steel specimen characterization is also discussed elsewhere, including the following references of note: [41][42][43][44][45], to name a few.…”