2026-08-27 合肥物質科学研究院（HFIPS）
Thermal stability and tensile properties of sintered Mo‑Hf alloys. (Image by ZHANG Yange)
＜関連情報＞
- https://english.hf.cas.cn/nr/rn/202608/t20260827_1189343.html
- https://www.sciencedirect.com/science/article/abs/pii/S1359645426007470
ナノスケールHf分散粒子のその場形成により、Mo合金において卓越した強度・延性シナジーと優れた熱安定性を実現 In-situ formation of nanoscale Hf dispersoids enabling exceptional strength-ductility synergy and superior thermal stability in Mo alloys
M.L. Yu, Y.G. Zhang, K.W. Li, H. Wang, Z.L. Huang, R. Liu, C.S. Liu, Z.M. Xie, X.B. Wu
Acta Materialia Available online: 11 August 2026
DOI:https://doi.org/10.1016/j.actamat.2026.122647
Abstract
Dispersion-strengthened molybdenum (Mo) alloys commonly suffer from severe performance degradation stemming from dispersoid coarsening or severe lattice misfit between the matrix and dispersed precipitates, which triggers interfacial debonding and premature intergranular fracture. Herein, we propose an in-situ nano-dispersion strengthening strategy by employing HfB2 as the Hf source for generating intragranular nanoparticles. Unlike conventional oxide-dispersion-strengthened Mo (ODS-Mo) with oxide particles preferentially segregating at grain boundaries, the present Mo-Hf alloy features ultrafine metallic Hf nanoparticles with an average diameter of ∼54 nm, approximately 84% of which are uniformly distributed inside Mo grain interiors. Combined first-principles calculations and experimental characterizations verify an ultra-small lattice misfit of only 0.04% and a low interface energy of 1.28 J/m2 for the Mo/Hf heterointerfaces. Such coherent interfacial architecture effectively suppresses interface-initiated cracking and endows intragranular Hf nanoparticles with outstanding thermal stability. Benefiting from this tailored intragranular nano-dispersion microstructure, the Mo-Hf alloy maintains exceptional tensile properties even after prolonged thermal annealing at 1000 °C for 100 h, achieving an ultimate tensile strength of 741 MPa and a tensile elongation of ∼24% at 400 °C. This work provides a feasible pathway to design high-performance Mo alloys balancing high strength, good ductility and exceptional thermal stability for high-temperature applications.
