{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T09:03:34Z","timestamp":1790327014012,"version":"4.1.0"},"reference-count":31,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T00:00:00Z","timestamp":1790294400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>To elucidate austenite grain coarsening and mixed-grain formation in continuously cast Nb\u2013Ti microalloyed steel during high-temperature holding, high-temperature holding experiments, Clyne\u2013Kurz microsegregation calculations, Thermo-Calc equilibrium precipitation analysis, Gladman pinning calculations, and multi-order-parameter phase-field simulations were combined to investigate the effect of precipitation differences between dendritic and interdendritic regions on heterogeneous austenite grain growth. The experimental results show that mixed-grain structures of varying severity are present after holding for 1 h at 1050\u20131300 \u00b0C. The austenite grains coarsen overall with increasing temperature, while pronounced coarsening of the initially fine-grained regions occurs above approximately 1200 \u00b0C. Microsegregation calculations suggest that Nb, Ti, and C are enriched in the interdendritic region, which may promote higher Nb(C,N) and TiN precipitation compared with the dendritic region. As temperature increases, grain-boundary mobility increases continuously. At 1150 \u00b0C, a considerable amount of precipitates remains in the interdendritic region, whereas pinning in the dendritic region is weaker, causing the difference in effective grain-boundary mobility between the two regions to increase. At higher temperatures, extensive dissolution of interdendritic Nb(C,N) reduces the regional difference in pinning and, consequently, the difference in effective grain-boundary mobility. The phase-field simulations capture the general characteristics of heterogeneous austenite grain-growth behavior and provide mechanistic insight into the influence of spatially varying effective grain-boundary mobility: at 1050 \u00b0C, low grain-boundary mobility and strong pinning result in slow grain coarsening; near 1150 \u00b0C, preferential growth in the dendritic region while the interdendritic region remains pinned produces the highest mixed-grain severity; at 1300 \u00b0C, extensive precipitate dissolution causes pronounced overall grain coarsening while reducing the regional grain-size contrast. The experimental observations were further interpreted using microsegregation and precipitation calculations to reveal the possible relationship between solidification-induced compositional heterogeneity and heterogeneous grain growth. These results indicate that local variations in effective grain-boundary mobility associated with solidification microsegregation are an important factor influencing the formation of mixed-grain structures.<\/jats:p>","DOI":"10.3390\/ma19194107","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T08:09:02Z","timestamp":1790323742000},"page":"4107","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Influence of Solidification Microsegregation on Heterogeneous Austenite Grain Growth in Nb\u2013Ti Microalloyed Steel: Experimental Investigation and Phase-Field Simulation"],"prefix":"10.3390","volume":"19","author":[{"given":"Haijie","family":"Wang","sequence":"first","affiliation":[{"name":"School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Haidian District, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Jian","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Materials and Physics Science, Nanchang University, No. 999 Xuefu Road, Honggutan District, Nanchang 330031, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"given":"Huasong","family":"Liu","sequence":"additional","affiliation":[{"name":"Institute for Special Steels, Central Iron and Steel Research Institute (CISRI), No. 76 Xueyuan South Road, Haidian District, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2941-1466","authenticated-orcid":false,"given":"Pu","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Materials and Physics Science, Nanchang University, No. 999 Xuefu Road, Honggutan District, Nanchang 330031, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"supervision","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Jiaquan","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Haidian District, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zhang, Y., and Ma, Y. 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