(中國科學(xué)院 金屬研究所，沈陽 110016)
摘 要: 研究了TC4ELI合金片層組織與短棒α組織中的疲勞裂紋尖端塑性區(qū)及裂紋擴(kuò)展行為。首先通過SEM及TEM觀察比較兩種顯微組織下的疲勞裂紋尖端塑性區(qū)，討論兩種顯微組織中裂紋尖端塑性區(qū)對疲勞裂紋擴(kuò)展路徑及擴(kuò)展斷口的影響，分析裂紋擴(kuò)展路徑和裂紋尖端塑性區(qū)對裂紋閉合及裂紋擴(kuò)展速率的影響。結(jié)果表明：與短棒α組織相比，片層組織中具有較大的裂紋尖端塑性區(qū)及曲折的裂紋擴(kuò)展路徑，并最終從疲勞裂紋閉合的角度，解釋了片層組織具有較低的疲勞裂紋擴(kuò)展速率的原因。
關(guān)鍵字: TC4ELI合金；裂紋尖端塑性區(qū)；裂紋閉合；疲勞裂紋擴(kuò)展速率
（Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The crack tip plastic zone (CTPZ) and fatigue crack propagation behavior of the lamellar and short-bar microstructures in TC4ELI alloy were studied. CTPZ of the two microstructures were compared by SEM and TEM observations. The influence of CTPZ on the crack propagating style and crack closure level were analyzed in the two microstructures. The results reveal that, compared with the short-bar microstructure, the larger CTPZ and flexuous crack propagating route in the lamellar microstructure induce high crack closure level that will decrease the fatigue crack growth (FCG) rates.
Key words: TC4ELI alloy; crack tip plastic zone; crack closure; fatigue crack growth rate
