Abstract
Improvement of the powdering resistance of galvannealed (GA) coatings is a key issue in automotive GA steel sheets. To make the relationship between powdering resistance and microstructure of GA layer, sputtering fabrication process was used to prepare Zn-Fe intermetallic films with various composition and microstructure in this study. Zn-Fe films with 1500 nm in thickness were deposited on an iron substrate by RF magnetron sputtering. Г+Г1 two-phase film (17.2~24.4 at.%Fe) was found to show a severe powdering by 3-point bending test, while Г1 (16.2 at.%Fe) or Г (34.3 at.%Fe) single-phase films showed much better powdering resistance. These results indicate that Г/Г1 interfaces boundaries have a low interfacial strength compared to that of Г/iron or Г1/iron interfaces. To improve the low powdering resistance of the Г+Г1 two-phase film, we investigated the effect of grain size refinement by B addition on the powdering resistance. It was found that the grain size refinement by B addition drastically improves the powdering resistance of Г+Г1 two-phase film. The decrease in the fracture toughness of Г+Г1 two-phase film by grain refinement was suggested to cause the improvement of its powdering resistance.
| Translated title of the contribution | Improvement of powdering resistance of Zn-Fe galvannealed coating by controlling of its composition and microstructure: Verification with sputtering method |
|---|---|
| Original language | Japanese |
| Pages (from-to) | 724-732 |
| Number of pages | 9 |
| Journal | Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan |
| Volume | 105 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2019 |
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Metals and Alloys
- Materials Chemistry