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An Insight into the Defects-Driven Plasticity in Ductile Cast Irons
Giuliano Angella1, Marcello Taloni1, Marcin Górny2
1Institute of Condensed Matter Chemistry and Technology for Energy (CNR-ICMATE), Department of Chemical Science and Materials Technology (DSCTM), Via R. Cozzi 53, 20125 Milan, Italy.
Materials (Basel, Switzerland)
|May 27, 2023
Summary
This study investigated defects in GJS400 castings, finding that Chunky Graphite (CHG) defects cause unexpected plastic behavior. A new material quality index was developed to assess casting integrity based on these findings.
Area of Science:
- Materials Science
- Metallurgy
- Mechanical Engineering
Background:
- Heavy section castings with GJS400 composition are prone to defects.
- Understanding defect impact on mechanical properties is crucial for integrity assessment.
Purpose of the Study:
- Investigate microstructure and tensile behavior of GJS400 castings.
- Quantify defect volume fractions and their effect on mechanical properties.
- Develop a new material quality index for casting integrity.
Main Methods:
- Conventional metallography and fractography.
- Micro-Computer Tomography (μ-CT) for defect quantification.
- Voce equation approach for tensile behavior analysis.
Main Results:
- Degenerated Chunky Graphite (CHG) identified as a major defect.
- Defects-Driven Plasticity (DDP) phenomenon observed, leading to linear Voce parameters in the Matrix Assessment Diagram (MAD).
- A pivotal point in strain hardening data linked to linearity in MAD.
Conclusions:
- CHG defects contribute to the linear distribution of Voce parameters in MAD.
- Linearity in MAD indicates a pivotal point in strain hardening data.
- A new material quality index based on this pivotal point can assess casting integrity.
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