孙铂涵 刘克伦 惠鹏飞 阮莹. 静电悬浮条件下Co-Ti-Nb合金的不规则共晶生长调控及蠕变机理[J]. 金属学报, DOI: 10.11900/0412.1961.2025.00141.

摘要 相关文章 Metrics 全文: PDF(4244 KB)   摘要: 钴基合金具有高耐热蚀性、优异的抗疲劳和抗氧化性，被广泛应用于航空航天和生物医学领域。为研究深过冷与快速凝固对合金晶体生长和微观力学性能的作用机制，本工作采用静电悬浮技术实现了Co35Ti35Nb30合金的深过冷与快速凝固，并结合纳米压痕方法对合金的抗蠕变性能进行了研究。合金的近平衡凝固组织为层片Co(Ti,Nb) + (Nb)共晶，这两相取向关系为{110}Co(Ti,Nb) // {110}(Nb) 和 <-113>Co(Ti,Nb) // <-113>(Nb)。在静电悬浮条件下，归因于共晶中两相的独立形核与竞争生长，合金微观组织随过冷度提升由层片共晶转变为不规则共晶。当过冷度达到273 K时，两相不再保持特定取向关系。由于过冷度增加引起的溶质截留效应和组织细化，合金维氏硬度和抗蠕变性能显著提升。随着过冷度从30 K增加至273 K，合金维氏硬度提升26.1 %，同一加载应变率下稳态蠕变阶段的蠕变应变率下降72.9 %。通过计算蠕变应力指数和活化体积，分析了合金的纳米压痕蠕变行为和机理。该合金的蠕变行为以位错运动为主，对加载应变率变化灵敏度低，在稳态蠕变阶段变形速率随加载应变率变化较小。 关键词 ： 共晶生长,  静电悬浮,  深过冷,  纳米蠕变     Abstract：Cobalt alloys, a series of high-temperature alloys with high thermal corrosion resistance, excellent fatigue resistance and oxidation resistance, have been commonly used as structural materials in the recent decades, especially in aerospace engineering and biomedical fields. In experimental, a sample was levitated between two vertical electrodes coupled with four side electrodes in a chamber evacuated to 1.0 × 10-5 Pa. When the levitated sample was heated and melted for several times by SPI SP300 laser, it solidified rapidly at high undercooling owing to the high-vacuum environment and containerless state. The rapid solidification mechanism and micromechanical properties of ternary Co35Ti35Nb30 alloy were investigated by means of electrostatic levitation (ESL). The microstructure of the alloy consists of Co(Ti,Nb) + (Nb) eutectic. An orientation relationship of {110}Co(Ti,Nb) // {110}(Nb) and <-113>Co(Ti,Nb) // <-113>(Nb) formed between Co(Ti,Nb) and (Nb) phases. Under ESL conditions, the microstructure transformed from lamellar to anomalous eutectic with increasing undercooling. The microstructure of the alloy underwent a transformation into a completely anomalous eutectic and had no crystallographic orientation relationship because of the independent growth of the two phases, at the maximum undercooling (273 K). The nanoindentation creep behavior and mechanism were analyzed by estimating the strain rate sensitivity and activation volume. Owing to the refinement of the rapidly solidified microstructure and the Ti solute trapping in the (Nb) phase, the resistance to dislocation motion of the alloy increased, and the microhardness and creep resistance of the alloy improved. With the undercooling increased from 30 to 273 K, the creep strain rate during the steady stage creep stage decreased by about an order of magnitude, from 1.03 × 10-4 s-1 to 2.79 × 10-5 s-1. In addition, increasing the loading strain rate promoted the proliferation of dislocations during loading, leading to an increase in strain rate sensitivity from 7.7 × 10-5 to 8.7 × 10-5 and a decrease in activation volume from 26.7 b3 to 25.7 b3. Key words： eutectic growth    electrostatic levitation    undercooling    nanoindentation creep 收稿日期: 2025-05-27      基金资助:国家自然科学基金;国家自然科学基金;国家自然科学基金;中国载人航天工程空间应用系统项目;秦创原“科学家+工程师”队伍建设项目 服务 把本文推荐给朋友 加入引用管理器 E-mail Alert RSS 作者相关文章 孙铂涵 刘克伦 惠鹏飞 阮莹 44.8K 链接本文: https://www.ams.org.cn/CN/Y0/V/I/0 [1] 王叶青, 付珂, 赵永柱, 苏礼季, 陈正. Fe7(CoNiMn)80B13 共晶高熵合金的深过冷非平衡凝固行为及微观组织演变[J]. 金属学报, 2025, 61(1): 143-153. [2] 许军锋, 张宝东, Peter K Galenko. 含有化合物相的共晶转变理论模型[J]. 金属学报, 2021, 57(10): 1320-1332. [3] 李金富, 周尧和. 液态金属深过冷快速凝固过程中初生固相的重熔[J]. 金属学报, 2018, 54(5): 627-636. [4] 翟斌, 周凯, 吕鹏, 王海鹏. 自由落体条件下Ti-6Al-4V合金微液滴的快速凝固研究[J]. 金属学报, 2018, 54(5): 824-830. [5] 朱姜蕾, 王庆, 王海鹏. 深过冷液态金属Cu的热物理性质和原子分布[J]. 金属学报, 2017, 53(8): 1018-1024. [6] 严军辉,坚增运,朱满,常芳娥,许军锋. 深过冷Al-70%Si合金的凝固特性与微观组织*[J]. 金属学报, 2016, 52(8): 931-937. [7] 郭雄，林鑫，汪志太，曹永青，彭东剑，黄卫东. 深过冷Ni-30Sn合金凝固组织演化及反常共晶的形成机制[J]. 金属学报, 2013, 29(4): 475-482. [8] 常芳娥 赵志伟 朱满 李娜 方雯 董广志 坚增运. 深过冷Ni-21.4%Si共晶合金的凝固特性研究[J]. 金属学报, 2012, 48(7): 875-881. [9] 穆丹宁 杨长林 魏晓伟 刘峰. 深过冷铁钴基块体合金的细晶化研究[J]. 金属学报, 2012, 48(12): 1409-1414. [10] 周圣银 胡锐 蒋力 李金山 寇宏超 常辉 周廉. 深过冷凝固Co80Pd20合金中的枝晶生长[J]. 金属学报, 2011, 47(4): 391-396. [11] 周俊 谢发勤 吴向清 张军. DZ125高温合金深过冷凝固组织转变规律[J]. 金属学报, 2009, 45(4): 385-389. [12] 杨长林; 杨根仓; 刘峰; 周尧和 . Fe-B共晶合金的净化及超过冷的获得[J]. 金属学报, 2008, 44(8): 956-960 . [13] 刘志光; 柴丽华; 陈玉勇; 孔凡涛 . 快速凝固TiAl化合物的研究进展[J]. 金属学报, 2008, 44(5): 569-573 . [14] 刘宁; 杨根仓; 刘峰; 陈豫增; 杨长林; 周尧和 . 深过冷Fe-Co合金的凝固规律[J]. 金属学报, 2007, 43(5): 449-453 . [15] 陈豫增; 杨根仓; 刘峰; 刘宁; 谢辉; 周尧和 . 过冷 Fe75Ni25合金晶粒细化机制的研究[J]. 金属学报, 2006, 42(7): 703-707 . Viewed Full text Abstract Cited   Shared      Discussed