Mon, 12 October, 2026
We are pleased to announce the publication of a new research paper in the ‘Materials and Design’ journal.
The paper, ‘Abnormal grain growth mitigation during powder hot isostatic pressing in mechanical alloyed oxide dispersion strengthened alloys,’ was authored by University of Birmingham PhD student Alice Appleby, with contributions from TWI technology consultant Dr Raja Khan, Prof Arunodaya Bhattacharya, Dr Liam Hughes and Prof Yu-Lung Chiu from the University of Birmingham and Loughborough University’s Prof Moataz M. Attallah.
Their excellent high temperature strength and resistance to several irradiation induced degradation mechanisms means that oxide dispersion strengthened (ODS) steels are promising structural material candidates for fast fission and fusion reactor in-vessel components.
However, these desirable properties depend upon microstructural features such as grain structure and nano-oxide distributions, which are directly controlled by the powder manufacturing, mechanical alloying and consolidation processes.
In fully ferritic ODS steels, where there is no phase transformation possibility, anisotropy during consolidation leading to heterogeneous mechanical properties remain a key concern. This is worsened by abnormal grain growth (AGG), resulting in very elongated and heterogeneous shaped grains.
This paper investigates the effect of powder hot isostatic pressing (P-HIP) temperature on microstructural evolution, demonstrating that high temperature HIP cycles can have a profound impact on consolidated ODS material’s microstructure, such as promoting nano-oxide coarsening and causing AGG.
Using mechanically alloyed PM2000 (Fe-20Cr-5.5Al-0.3Y2O3) as an exemplar the paper shows that a dual-dwell HIP cycle, incorporating an initial low temperature hold can effectively relieve internal stresses in mechanically alloyed powder material, minimising AGG and improving tensile ductility as compared to a similar single dwell HIP cycle.
You can see the paper in full, here:
https://www.sciencedirect.com/science/article/pii/S0264127526017570