Rajaee Ali, Asadabad Mohsen Asadi, Boroujeny Behrooz Shayegh
Department of Materials Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar, Iran.
Nuclear Science and Technology Research Institute, Tehran, Iran.
Heliyon. 2025 Jan 9;11(2):e41834. doi: 10.1016/j.heliyon.2025.e41834. eCollection 2025 Jan 30.
In the current study, the effect of direction on the hot compression behavior, processing map, and microstructure of Zr-Nb alloy after bidirectional hot forging was studied. Accordingly, the alloy billet was hot-forged and samples at different directions were extracted. Phase changes and microstructure of the samples were characterized. Additionally, hot compression tests were carried out on the samples in the temperature and strain rate ranges of 800-900 °C and 0.001-1 s, respectively. Microstructure examinations revealed that the forging resulted in the formation of various alpha spherical grains elongated along the forging direction. Along the directions of 30 and 60°, the high strain rate during forging caused the formation of secondary recrystallized grains in addition to grains elongated in the forging direction. Hardness measurement results showed that the highest hardness was related to the zero-degree direction due to the high fraction, refinement, and morphology of the alpha phase formed during the hot forging process. Full recrystallization of hot-compression samples was evident at 850 °C. Processing maps suggested the optimum deformation of the alloy to be within the strain rates 0.01-0.001 at 850 °C. Consequently, deformation within this range results in the desired dynamic recrystallization phenomenon.
在当前研究中，研究了双向热锻后方向对Zr-Nb合金热压缩行为、加工图和微观结构的影响。据此，对合金坯料进行热锻，并提取不同方向的样品。对样品的相变和微观结构进行了表征。此外，分别在800-900°C的温度范围和0.001-1 s的应变速率范围内对样品进行了热压缩试验。微观结构检查表明，锻造导致沿锻造方向形成各种拉长的α球形晶粒。在30°和60°方向上，锻造过程中的高应变速率除了导致沿锻造方向拉长的晶粒外，还导致了二次再结晶晶粒的形成。硬度测量结果表明，由于热锻过程中形成的α相的高比例、细化和形态，最高硬度与零度方向有关。热压缩样品在850°C时完全再结晶明显。加工图表明，合金在850°C下的最佳变形应在0.01-0.001的应变速率范围内。因此，在此范围内的变形会导致所需的动态再结晶现象。
