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

2021 ◽  
Vol 1160 ◽  
pp. 83-91
Author(s):  
M. Karam-Abian ◽  
A. Zarei-Hanzaki ◽  
A.H. Shafieizad ◽  
A. Zinsaz-Borujerdi ◽  
S. Ghodrat
Keyword(s):  
Plastic Flow ◽  
Flow Behavior ◽  
Strain Curve ◽  
Bulk Sample ◽  
Constraint Factor ◽  
Flow Curves ◽  
Factor Ii ◽  
Successful Prediction ◽  
Tensile Curve ◽  
Using Data

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.

Predicting macroscopic plastic flow of high-performance, dual-phase steel through spherical nanoindentation on each microphase

2009 ◽  
Vol 24 (3) ◽  
pp. 816-822 ◽  
Author(s):  
Byoung-Wook Choi ◽  
Dong-Han Seo ◽  
Jang-Yong Yoo ◽  
Jae-il Jang
Keyword(s):  
Plastic Flow ◽  
High Performance ◽  
Dual Phase Steel ◽  
Pipeline Steel ◽  
Strain Curve ◽  
Indentation Hardness ◽  
Additional Consideration ◽  
Constraint Factor ◽  
Stress Strain ◽  
Soft Ferrite

An attempt was made to predict the macroscopic plastic flow of a high-performance pipeline steel, consisting of dual constituent phases (soft ferrite and hard bainite), by performing nanoindentation experiments on each microphase with two spherical indenters that have different radii (550 nm and 3.3 μm). The procedure is based on the well known concepts of indentation stress-strain and constraint factor, which make it possible to relate indentation hardness to the plastic flow of the phases. Additional consideration of the indentation size effect for sphere and application of a simple “rule-of-mixture” led us to a reasonably successful estimation of the macroscopic plastic flow of the steel from the microphases properties, which was verified by comparing the predicted stress-strain curve with that directly measured from the conventional tensile test of a bulky sample.

Constitutive Modeling of Low-Temperature Superplastic Flow of Ultrafine Ti-6Al-4V Sheet Material

2010 ◽  
Vol 433 ◽  
pp. 235-240 ◽  
Author(s):  
S. Lee Semiatin ◽  
Gordon A. Sargent
Keyword(s):  
Low Temperature ◽  
Flow Behavior ◽  
Sheet Material ◽  
Superplastic Flow ◽  
Flow Softening ◽  
Flow Localization ◽  
Flow Curves ◽  
Localization Model ◽  
Simple Flow ◽  
Stress Flow

The low-temperature superplastic flow behavior of two lots of Ti-6Al-4V sheet with an ultrafine microstructure was modeled. One lot (Sheet A) had an equiaxed-alpha starting microstructure; the flow stress/flow hardening exhibited by this material was explained on the basis of the Bird-Mukherjee-Dorn constitutive equation. The other material (Sheet B), having a mixed equiaxed- and remnant-lamellar alpha microstructure, underwent flow softening, flow hardening, or steady-state flow depending on test temperature and strain rate. These behaviors were interpreted in the context of a dynamic spheroidization model. The apparent flow softening at the end of all of the flow curves was explained using a simple flow-localization model.

scholarly journals Influence of Deformation Controlled Strain Rate on Tensile and Compression Behaviour of Magnesium and Steel Wire

2017 ◽  
Vol 892 ◽  
pp. 89-96 ◽  
Author(s):  
Thorsten Henseler ◽  
Madlen Ullmann ◽  
Grzegorz Korpala ◽  
Klaudia Klimaszewska ◽  
Rudolf Kawalla ◽  
...  
Keyword(s):  
Strain Rate ◽  
Elevated Temperatures ◽  
Steel Wire ◽  
Testing Machine ◽  
Constant Strain Rate ◽  
Strain Curve ◽  
Compression Testing ◽  
Uniaxial Tensile ◽  
Flow Curves ◽  
The Difference

This article demonstrates the difference in the flow curves of an AZ31 magnesium alloy and S235JR structural steel wire caused by non-linear strain rates during uniaxial tensile and compression testing at elevated temperatures. Throughout tensile deformation, the traverse velocity of the testing machine has to be adapted according to the current elongation of the specimen, thus accelerating, to ensure a constant strain rate during the admission of the stress-strain curve. The equivalent is necessary during compression testing, where the traverse velocity of the testing machine needs to decelerate ensuring a constant strain rate. Nevertheless, tensile and compression tests are performed with constant traverse velocity, which lead to divergent flow curves in comparison to deformation controlled traverse velocities. The results of the research show the difference in flow behaviour of magnesium and steel wire, when the temperature and strain rate are varied in conjunction with constant and deformation controlled traverse velocities.

scholarly journals Plastic flow behavior during the forging of a 6061 Al/10 vol pct Al2O3 (p) composite

2000 ◽  
Vol 31 (4) ◽  
pp. 1310-1313 ◽  
Author(s):  
M. S. Yeh ◽  
W. P. Weng ◽  
S. C. Wang ◽  
T. H. Chuang
Keyword(s):  
Plastic Flow ◽  
Flow Behavior
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