{"title":"Effect of thermomechanical processing on the grain boundary character distribution of phosphorus bronze","authors":"","doi":"10.1016/j.matchar.2024.114401","DOIUrl":null,"url":null,"abstract":"<div><div>Grain boundary engineering (GBE) is widely adopted to improve the grain boundary (GB) character distribution (GBCD) of face-centered-cubic (FCC) metals. In phosphorus bronze alloy, achieving an optimized GBCD while maintaining sufficiently small grain size is critical for maintaining high strength and excellent bending workability. However, the precise evolution and formation mechanisms of GBs during GBE remain unclear to date. Leveraging electron backscatter diffraction and transmission electron microscopy analyses, this study examined the effect of thermomechanical processing (TMP) on GBCD optimization and twin-related domain (TRD) evolution in phosphorus bronze. The results revealed that strain-induced boundary migration (SIBM) plays a pivotal role in GBCD optimization. In particular, SIBM facilitates the formation of abundant new Σ3 boundaries behind migrating GB fronts, thus increasing the proportion of special boundaries (SBs) and introducing low-energy segments such as Σ9 and Σ27 boundaries. These boundaries effectively disrupt the connectivity of the random high angle grain boundary (RHAGB) network. Furthermore, the results indicate that the optimal TMP conditions for GBCD optimization include a reduction level of 5 %, annealing temperature of 450 °C, and annealing duration of 1 h. These conditions result in an average grain size being <3 μm and the GB fractions <em>f</em><sub>SBs</sub> and <em>f</em><sub>Σ9+Σ27</sub> being 81.3 % and 9.8 %, respectively. Deformation twins formed within the deformed microstructure inhibit TRD growth, thus hindering GBCD optimization. Additionally, the optimal strain threshold for GBCD optimization lies near the strain threshold for the formation of deformation twins. TRDs form during the primary recrystallization process, while high-order twin boundaries form behind the migration front during the growth process.</div></div>","PeriodicalId":18727,"journal":{"name":"Materials Characterization","volume":null,"pages":null},"PeriodicalIF":4.8000,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Materials Characterization","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1044580324007824","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, CHARACTERIZATION & TESTING","Score":null,"Total":0}
引用次数: 0
Abstract
Grain boundary engineering (GBE) is widely adopted to improve the grain boundary (GB) character distribution (GBCD) of face-centered-cubic (FCC) metals. In phosphorus bronze alloy, achieving an optimized GBCD while maintaining sufficiently small grain size is critical for maintaining high strength and excellent bending workability. However, the precise evolution and formation mechanisms of GBs during GBE remain unclear to date. Leveraging electron backscatter diffraction and transmission electron microscopy analyses, this study examined the effect of thermomechanical processing (TMP) on GBCD optimization and twin-related domain (TRD) evolution in phosphorus bronze. The results revealed that strain-induced boundary migration (SIBM) plays a pivotal role in GBCD optimization. In particular, SIBM facilitates the formation of abundant new Σ3 boundaries behind migrating GB fronts, thus increasing the proportion of special boundaries (SBs) and introducing low-energy segments such as Σ9 and Σ27 boundaries. These boundaries effectively disrupt the connectivity of the random high angle grain boundary (RHAGB) network. Furthermore, the results indicate that the optimal TMP conditions for GBCD optimization include a reduction level of 5 %, annealing temperature of 450 °C, and annealing duration of 1 h. These conditions result in an average grain size being <3 μm and the GB fractions fSBs and fΣ9+Σ27 being 81.3 % and 9.8 %, respectively. Deformation twins formed within the deformed microstructure inhibit TRD growth, thus hindering GBCD optimization. Additionally, the optimal strain threshold for GBCD optimization lies near the strain threshold for the formation of deformation twins. TRDs form during the primary recrystallization process, while high-order twin boundaries form behind the migration front during the growth process.
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.