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Sen Yang, Zhiren Sun, Zipeng Wang, Shuhui Zhao, Kaikun Wang, Dun Li, and Xiaokai Wang, Microstructural optimization and strengthening mechanisms of in-situ TiB2/Al–Cu composite after multidirectional forging for six passes, Int. J. Miner. Metall. Mater., (2025). https://doi.org/10.1007/s12613-024-3058-6
Sen Yang, Zhiren Sun, Zipeng Wang, Shuhui Zhao, Kaikun Wang, Dun Li, and Xiaokai Wang, Microstructural optimization and strengthening mechanisms of in-situ TiB2/Al–Cu composite after multidirectional forging for six passes, Int. J. Miner. Metall. Mater., (2025). https://doi.org/10.1007/s12613-024-3058-6
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六道次多向锻造TiB2/Al–Cu复合材料的组织优化与强化机制研究

摘要: 颗粒增强铝基复合材料因其轻质、高比强度和高比刚度等优势,广泛应用于航空航天、汽车与装备制造等领域。但其在铸态下普遍存在组织粗大和TiB2颗粒分布不均等问题,限制了力学性能的进一步提升。本文以原位TiB2/Al–Cu复合材料为研究对象,采用微观组织表征、显微硬度测试及拉伸性能测试等手段,研究了锻件不同区域的组织特征(包括晶粒细化与TiB2颗粒分布)与等效应变之间的关系,以及微观组织对锻后力学性能的影响。研究结果表明,MDF过程中引入的大塑性应变促使原始α-Al晶粒发生机械几何破碎,并诱发不连续动态再结晶(DDRX)、连续动态再结晶(CDRX)及粒子刺激形核再结晶(PSN–DRX)等机制,有效促进组织细化。锻件各区域的等效应变存在较大差异,其中锻件中心区域等效应变最大,晶粒细化最为显著,平均晶粒尺寸为15.6  μm,再结晶晶粒比例达到22.49%。同时,TiB2颗粒的团聚现象得到明显改善,分布更加均匀。该区域显微硬度由铸态的HV 79.56提高至HV 91.31,抗拉强度和屈服强度较铸态分别提高51.2%和54%。性能提升主要归因于细晶强化与位错强化的协同作用,其中MDF过程中形成的大量高密度位错是强度增强的关键因素。由此得到结论:高等效应变有助于晶粒破碎与再结晶形成,同时改善TiB2颗粒的分布状态,进而提升复合材料的整体力学性能。

 

Microstructural optimization and strengthening mechanisms of in-situ TiB2/Al–Cu composite after multidirectional forging for six passes

Abstract: In-situ TiB2/Al–Cu composite was processed by multidirectional forging (MDF) for six passes. The microstructure evolution of the forged workpiece was examined across various regions. The mechanical properties of the as-cast and MDFed composites were compared, and their strengthening mechanisms were analyzed. Results indicate that the grain refinement achieved through the MDF process is mainly due to the subdivision of the original grains through mechanical geometric fragmentation and the occurrence of dynamic recrystallization (DRX). DRX grains are formed through discontinuous DRX, continuous DRX, and recrystallization induced by particle-stimulated nucleation. A rise in accumulated equivalent strain ( \Sigma \Delta \varepsilon ) results in finer α-Al grains and a more uniform distribution of TiB2 particles, which enhance the Vickers hardness of the composite. In addition, the tensile properties of the MDFed composite significantly improve compared with those of the as-cast composites, with ultimate tensile strength and yield strength increasing by 51.2% and 54%, respectively. This enhancement is primarily due to grain refinement strengthening and dislocation strengthening achieved by the MDF process.

 

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