Precipitation behavior of silicide and synergetic strengthening mechanisms in TiB-reinforced high-temperature titanium matrix composites during multi-directional forging
Precipitation behavior of silicide and synergetic strengthening mechanisms in TiB-reinforced high-temperature titanium matrix composites during multi-directional forging
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DOI：
10.1016/j.jallcom.2021.159051
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发表时间：
2021-02-10
影响因子：
6.2
通讯作者：
Chen, Wenzhen
中科院分区：
文献类型：
--
作者：
Sun, Shichen;Zhao, Ertuan;Chen, Wenzhen
为了研究硅化物的析出行为和评价增强相对钛基复合材料性能的贡献，采用真空感应熔融多向锻造法制备了tib增强高温钛基复合材料。多向锻造复合材料的显微组织由球化的a相、均匀分布的TiB和双尺度硅化物组成。硅化物的析出是由于锻造过程中位错加速了元素的扩散。由于a相的细晶强化和硅化物的析出强化，室温多向锻造后复合材料的强度提高了151.9 MPa左右，而TiB晶须的承载效率随着长径比的减小而降低。在700℃时，多向锻造钛基复合材料的强度降低约28.3 MPa。但塑性明显提高，伸长率达到116.8%。导致强度下降的主要原因是晶界容易萌生裂纹和硅化物的析出强化减弱。(C) 2021 Elsevier B.V.版权所有
To investigate the precipitation behavior of silicide and evaluate the contribution of the reinforcement phase to the properties of titanium matrix composites, a TiB-reinforced high-temperature titanium matrix composite was prepared by vacuum induction melting and multi-directional forging. The microstructure of the resultant composite after multi-directional forging was composed of a spheroidized a-phase, uniformly-distributed TiB and dual-scale silicides. The precipitation of silicides was attributed to the acceleration of elemental diffusion due to dislocations during forging. The strength of the composite after multi-directional forging at room temperature increased by about 151.9 MPa due to the fine-grain strengthening of the a-phase and the precipitation strengthening of the silicides, whereas the load-bearing efficiency of the TiB whiskers was reduced with the decrease in the aspect ratio. The strength of the multi-directional-forged titanium matrix composite at 700 degrees C was reduced by about 28.3 MPa. However, its plasticity was sig-nificantly improved, and the elongation reached 116.8%. The main reasons for the decrease in the strength were the easy initiation of cracks the grain boundaries and the weakening of the precipitation strengthening of the silicides. (C) 2021 Elsevier B.V. All rights reserved.