Determining individual phase properties in a multi-phase Q&P steel using multi-scale indentation tests

Abstract

a b s t r a c tA new inverse method was developed to predict the stress-strain behaviors of constituent phases in a multi-phase steel using the load-depth curves measured in nanoindentation tests combined with microhardness measurements. A power law hardening response was assumed for each phase, and an empirical relationship between hardness and yield strength was assumed. Adjustment was made to eliminate the indentation size effect and indenter bluntness effect. With the newly developed inverse method and statistical analysis of the hardness histogram for each phase, the average stress-strain curves of individual phases in a quench and partitioning (Q&P) steel, including austenite, tempered martensite and untempered martensite, were calculated and the results were compared with the phase properties obtained by in-situ high energy X-ray diffraction (HEXRD) test. It is demonstrated that multiscale instrumented indentation tests together with the new inverse method are capable of determining the individual phase flow properties in multi-phase alloys.

Influence of Bi addition on the property of Ag-Bi nano-composite coatings

“…Nanoindentation is a small-scale in-situ testing and characterization method which has been widely used for coatings, thin films and bulk polycrystalline materials [26][27][28][29][30][31][32].…”

Microstructural Evolution of Nb–V–Mo and V Containing TRIP-assisted Steels during Thermomechanical Processing

“…33 HV0.1) can be mainly related to the inhomogeneous distribution of martensite, bainite, retained austenite and precipitates in these regions. In other words, different constituents in multiphase steels have different hardness and their volume fraction and distribution can change the overall hardness [39,40] . It can be thus inferred that the most likely reasons for the high hardness of Steel 2 was attributed to the martensite/bainite volume fraction and also precipitation strengthening.…”

Effect of Precipitation on the Hardness of Ternary Metallic Glass

“…Also, previous studies have demonstrated that annealing-induced hardening might be possible in bulk metallic glasses (BMG) [9] [15]. Multi-scaling indentation as well as different inverse methods can be utilized to access the elastic properties [16] and plastic properties of individual grains [17] [18] and individual phases [19]. Besides, the application of multi-direction indentation will be helpful to understand the possible anisotropy of REMGs foils [20].…”