Microstructural strengthening and toughening mechanisms in Fe-containing Ti-6Al-4V: A comparison between homogenization and aging treated states
Microstructural strengthening and toughening mechanisms in Fe-containing Ti-6Al-4V: A comparison between homogenization and aging treated states
复制标题
含铁Ti-6Al-4V的显微组织强化和增韧机制：均匀化和时效处理状态的比较
DOI：
10.1016/j.jmst.2021.04.063
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发表时间：
2021-09-08
影响因子：
10.9
通讯作者：
Cui, Yuwen
中科院分区：
文献类型：
--
作者：
Liao, Yu;Bai, Junhua;Cui, Yuwen
添加Fe的微合金化Ti-6Al-4V合金是改善铸造性能和综合力学性能的一种很有前途的方法。本工作的任务是通过实验检验和唯象分析，(1)研究Fe的加入对含Fe的Ti-6Al-4V(TC4-XF)合金铸态和均匀化处理后的组织特征和力学性能的影响，以及(2)揭示在均匀化、热加工和时效处理中分别对屈服强度和断裂韧性有利的临界组织特征。实验观察表明，添加0.5wt.%Fe对提高合金的拉伸塑性和I型断裂韧性最为有效。此外，铁的加入量高达0.7-0.9wt.%，导致屈服和极限强度的平台值，但有一些波动。唯象分析筛选出了组织强韧化决定因素，它们在不同的加工条件下对铁含量表现出明显的敏感性。结果表明，固溶强化是控制TC4-XF合金屈服强度的主要因素，其次是团簇和片层的细化，热加工和时效处理的TC4-XF合金也是如此。热加工可以进一步提高Fe的强化效果，但延长退火时间或降低冷却速度会削弱Fe的强化效果。在不同的情况下，裂纹扩展路径的类型和α形态对断裂韧性的影响各有其主导作用。横跨宽大的α/β层片的长裂纹扩展距离包含高的裂纹扩展阻力，并产生增强的断裂韧性。实验结果丰富了Ti-6Al-4V相关合金的组织特征和力学性能的数据集。而在唯象分析的基础上，所发现的微观组织强韧化因素为Fe变质的Ti-6Al-4V合金的力学行为提供了更深层次的机理洞察，并对未来组织-性能关系的机器学习具有重要的技术意义。(C)由爱思唯尔有限公司代表《材料科学与技术杂志》编辑部出版的《2022》。
Microalloying of Ti-6Al-4V alloy by Fe addition has attracted interest as a promising way to improve castability and comprehensive mechanical performance. The mission of this work is twofold by employing the experimental examination and the phenomenological analysis, (1) to investigate the effect of Fe addition on the microstructure features and mechanical properties of the Fe-containing Ti-6Al-4V (TC4-xF) alloys subjected to casting and homogenization treatment, and (2) to unveil the critical microstructure features in homogenization, hot-worked and aging treated alloys, respectively, that benefit the yield strength and the fracture toughness. Experimental observations evidence that the addition of 0.5 wt.% Fe is most effective in enhancing the tensile ductility and the mode I fracture toughness. Further Fe addition up to 0.7-0.9 wt.% results in plateau values of yield and ultimate strengths with some fluctuations. Phenomenological analyses screen out the microstructural strengthening and toughening determinants which exhibit distinct sensitivities on Fe content under different processing conditions. The solid solution strengthening is confirmed as the primary effect that governs the yield strength of the homogenization treated TC4-xF alloys, followed by the refined size of colony and a lamella, so does it for the hot-worked and the aging-treated alloys. The strengthening effect of Fe could be further promoted by hot-working but impaired by a prolonged annealing time or a lowered cooling rate. The type of crack propagation path and the a morphology are discerned to play their own leading roles in different cases to influence the performance of fracture toughness. A long crack propagation distance that traverses broad alpha/beta lamellae embraces a high crack propagation resistance and gives rise to enhanced fracture toughness. The experimental results enrich the dataset of microstructure features and mechanical properties of Ti-6Al-4V relevant alloys. While upon the phenomenological analysis, the discovered microstructural strengthening and toughening factors provide deeper mechanism insights into the mechanical behaviors of Fe-modified Ti-6Al-4 V alloys and are of the technical importance to future machine-learning of microstructure-property relationship. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.