Mo-Re alloys microstructure evolution during high-pressure torsion

IF 5.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization Pub Date : 2025-09-04 DOI:10.1016/j.matchar.2025.115538

Ivan A. Ditenberg

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Abstract

The features of the microstructure evolution of Mo-47 %Re alloys under severe plastic deformation by high-pressure torsion were studied. Using the dark-field analysis of discrete and continuous misorientations, depending on the plastic deformation degree, a quantitative certification of the parameters of highly defective structural states was carried out. The main mechanisms of formation of ultrafine-grained and nanocrystalline structural states were revealed. By measuring at different distances from the torsion axis in sections perpendicular to the anvil plane, the microhardness values of the studied alloys were determined, the maximum values of which reach more than 12 GPa. It was established that a decrease in microhardness in the peripheral part at maximum realized deformation values is associated with the formation of cracks along grain boundaries. An analysis of the microstructure transformation features of the studied alloys in a “high-strength state” formed during high-pressure torsion was carried out. It is assumed that under these conditions the dislocation-disclination mechanism and the mechanism of lattice reorientation by quasi-viscous flows of nonequilibrium point defects are the main mechanisms of structural transformation of Mo-47 %Re alloys at the submicrocrystalline and nanoscale levels, respectively.

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高压扭转过程中Mo-Re合金组织演变

研究了mo - 47% Re合金在高压扭转剧烈塑性变形下的组织演变特征。利用离散和连续取向的暗场分析，根据塑性变形程度，对高缺陷结构状态的参数进行了定量验证。揭示了超细晶和纳米晶结构态形成的主要机理。通过在垂直于砧面截面上距离扭转轴不同距离处的测量，测定了合金的显微硬度值，其最大值可达12 GPa以上。结果表明，在最大实现变形值处，外围部分显微硬度的下降与沿晶界裂纹的形成有关。分析了合金在高压扭转过程中形成的“高强状态”的组织转变特征。在此条件下，位错偏斜机制和非平衡点缺陷的准粘性流动导致的晶格重定向机制分别是mo - 47% Re合金在亚微晶和纳米级结构转变的主要机制。

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来源期刊

Materials Characterization 工程技术-材料科学：表征与测试

CiteScore

7.60

自引率

8.50%

发文量

746

审稿时长

36 days

期刊介绍： Materials Characterization features original articles and state-of-the-art reviews on theoretical and practical aspects of the structure and behaviour of materials. The Journal focuses on all characterization techniques, including all forms of microscopy (light, electron, acoustic, etc.,) and analysis (especially microanalysis and surface analytical techniques). Developments in both this wide range of techniques and their application to the quantification of the microstructure of materials are essential facets of the Journal. The Journal provides the Materials Scientist/Engineer with up-to-date information on many types of materials with an underlying theme of explaining the behavior of materials using novel approaches. Materials covered by the journal include: Metals & Alloys Ceramics Nanomaterials Biomedical materials Optical materials Composites Natural Materials.