Evolution of Precipitation in the new Hybrid Steel
| Reference number | |
| Coordinator | CHALMERS TEKNISKA HÖGSKOLA AKTIEBOLAG - Institutionen för fysik |
| Funding from Vinnova | SEK 490 000 |
| Project duration | November 2018 - February 2020 |
| Status | Completed |
| Venture | Research infrastructure - utilisation and collaboration |
| Call | Research infrastructure - utilisation and collaboration: Industrial pilot projects for neutron and photon experiments at large scale research infrastructures - 2018 |
| End-of-project report | 2018-04433_Ovako.pdf (pdf, 420 kB) |
Important results from the project
The purpose of the project was to conduct experiments where scattering of synchrotron X-rays are used to obtain information about the precipitation process in a material, in this case Hybrid Steel® from Ovako. This steel is hardened by both inter-metallic NiAl-particles and carbides. The samples were placed in a furnace, so that the process could be studied in real time during heat-treatment. The results showed how the NiAl-particles grew depending on time and temperature, and some information could also be obtained from secondary carbides, which was the goal of the project.
Expected long term effects
The results from the in-situ experiments clearly showed the development of NiAl-particles during heat-treatment. This knowledge is expected to be valuable for Ovako and their customers in order to tailor heat-treatments for different applications. The growth of carbides was harder to interpret and further data analysis as well as complementary studies are likely needed. The changes in lattice parameters and the fraction of austenite gave unforeseen information, which resulted in improved understanding of how the microstructure develops during heat-treatment and cooling.
Approach and implementation
The experiments were carried out at the beam line P21, Petra III in Hamburg. They were done in-situ, at temperatures between 500 and 600C, mostly for 4-7 h. The in-situ measurements were complemented by ex-situ studies, in particular for long heat-treatment times. WAXS, which gives structure information, like XRD, and SAXS, which gives particle size, where done in parallel. The data evaluation was rather complicated as the carbide volume fraction was relatively small, and there were some peak overlaps. The data for the NiAl-particles was clear and provided important information.